~ubuntu-branches/ubuntu/vivid/basilisk2/vivid

Viewing changes to src/slirp/tcp_input.c

Committer: Bazaar Package Importer
Author(s): Jonas Smedegaard
Date: 2008-03-06 19:33:01 UTC
mfrom: (2.1.4 gutsy)
Revision ID: james.westby@ubuntu.com-20080306193301-cc2ofn705nfsq3y0

Tags: 0.9.20070407-4

* Update copyright-check cdbs snippet to parse licensecheck using perl:
  + No longer randomly drops newlines
  + More compact hint file (and ordered more like wiki-proposed new copyright
    syntax).
  + No longer ignore files without copyright.
* Update copyright_hints.

files added:
ChangeLog.cvs

debian/README.cdbs-tweaks

debian/cdbs/1

debian/cdbs/1/rules

debian/cdbs/1/rules/buildinfo.mk

debian/cdbs/1/rules/copyright-check.mk

debian/cdbs/1/rules/upstream-tarball.mk

debian/control.in

debian/copyright_hints

debian/patches

debian/patches/1001_mention_Macintosh_in_manpage.patch

debian/patches/1002_fix-capitalized-flag.patch

debian/patches/1003_avoid_undefined_HAVE_SIGSEGV_RECOVERY_1.patch

debian/patches/2001_avoid_stripping_binaries.patch

debian/patches/README

debian/patches/series

src/MacOSX/AudioBackEnd.cpp

src/MacOSX/AudioBackEnd.h

src/MacOSX/AudioDevice.cpp

src/MacOSX/AudioDevice.h

src/MacOSX/BasiliskII.xcode

src/MacOSX/BasiliskII.xcode/project.pbxproj

src/MacOSX/Info.plist

src/MacOSX/MacOSX_sound_if.cpp

src/MacOSX/MacOSX_sound_if.h

src/MacOSX/clip_macosx.cpp

src/SDL

src/SDL/audio_sdl.cpp

src/SDL/keycodes

src/SDL/video_sdl.cpp

src/Unix/Darwin

src/Unix/Darwin/gtk-osx.patch

src/Unix/Darwin/lowmem.c

src/Unix/Darwin/mkstandalone

src/Unix/Darwin/pagezero.c

src/Unix/Darwin/testlmem.sh

src/Unix/ldscripts

src/Unix/ldscripts/freebsd-i386.ld

src/Unix/ldscripts/linux-i386.ld

src/Unix/ldscripts/linux-ppc.ld

src/Unix/ldscripts/linux-x86_64.ld

src/Unix/m4

src/Unix/m4/egrep.m4

src/Unix/m4/esd.m4

src/Unix/m4/gettext.m4

src/Unix/m4/gtk-2.0.m4

src/Unix/m4/gtk.m4

src/Unix/rpc.h

src/Unix/rpc_unix.cpp

src/Unix/tunconfig

src/Windows

src/Windows/BasiliskII.ico

src/Windows/BasiliskII.rc

src/Windows/BasiliskIIGUI.ico

src/Windows/BasiliskIIGUI.rc

src/Windows/Makefile.in

src/Windows/b2ether

src/Windows/b2ether/inc

src/Windows/b2ether/inc/b2ether_hl.h

src/Windows/b2ether/inc/ntddpack.h

src/Windows/b2ether/multiopt.h

src/Windows/b2ether/packet32.cpp

src/Windows/cd_defs.h

src/Windows/cdenable

src/Windows/cdenable/cache.cpp

src/Windows/cdenable/cache.h

src/Windows/cdenable/cdenable.h

src/Windows/cdenable/eject_nt.cpp

src/Windows/cdenable/eject_nt.h

src/Windows/cdenable/ntcd.cpp

src/Windows/cdenable/ntcd.h

src/Windows/clip_windows.cpp

src/Windows/configure.ac

src/Windows/ether_windows.cpp

src/Windows/ether_windows.h

src/Windows/extfs_windows.cpp

src/Windows/kernel_windows.cpp

src/Windows/kernel_windows.h

src/Windows/main_windows.cpp

src/Windows/posix_emu.cpp

src/Windows/posix_emu.h

src/Windows/prefs_editor_gtk.cpp

src/Windows/prefs_windows.cpp

src/Windows/router

src/Windows/router/arp.cpp

src/Windows/router/arp.h

src/Windows/router/dump.cpp

src/Windows/router/dump.h

src/Windows/router/dynsockets.cpp

src/Windows/router/dynsockets.h

src/Windows/router/ftp.cpp

src/Windows/router/ftp.h

src/Windows/router/icmp.cpp

src/Windows/router/icmp.h

src/Windows/router/iphelp.cpp

src/Windows/router/iphelp.h

src/Windows/router/ipsocket.cpp

src/Windows/router/ipsocket.h

src/Windows/router/mib

src/Windows/router/mib/interfaces.cpp

src/Windows/router/mib/interfaces.h

src/Windows/router/mib/mibaccess.cpp

src/Windows/router/mib/mibaccess.h

src/Windows/router/router.cpp

src/Windows/router/router.h

src/Windows/router/router_types.h

src/Windows/router/tcp.cpp

src/Windows/router/tcp.h

src/Windows/router/udp.cpp

src/Windows/router/udp.h

src/Windows/serial_windows.cpp

src/Windows/sys_windows.cpp

src/Windows/sysdeps.h

src/Windows/timer_windows.cpp

src/Windows/user_strings_windows.cpp

src/Windows/user_strings_windows.h

src/Windows/util_windows.cpp

src/Windows/util_windows.h

src/Windows/xpram_windows.cpp

src/slirp

src/slirp/COPYRIGHT

src/slirp/bootp.c

src/slirp/bootp.h

src/slirp/cksum.c

src/slirp/ctl.h

src/slirp/debug.c

src/slirp/debug.h

src/slirp/icmp_var.h

src/slirp/if.c

src/slirp/if.h

src/slirp/ip.h

src/slirp/ip_icmp.c

src/slirp/ip_icmp.h

src/slirp/ip_input.c

src/slirp/ip_output.c

src/slirp/libslirp.h

src/slirp/main.h

src/slirp/mbuf.c

src/slirp/mbuf.h

src/slirp/misc.c

src/slirp/misc.h

src/slirp/sbuf.c

src/slirp/sbuf.h

src/slirp/slirp.c

src/slirp/slirp.h

src/slirp/slirp_config.h

src/slirp/socket.c

src/slirp/socket.h

src/slirp/tcp.h

src/slirp/tcp_input.c

src/slirp/tcp_output.c

src/slirp/tcp_subr.c

src/slirp/tcp_timer.c

src/slirp/tcp_timer.h

src/slirp/tcp_var.h

src/slirp/tcpip.h

src/slirp/tftp.c

src/slirp/tftp.h

src/slirp/udp.c

src/slirp/udp.h

src/uae_cpu/compiler/test_codegen_x86.cpp

files removed:
debian/cdbs/autotools-vars.mk

src/MacOSX/BasiliskII.pbproj/nigel.pbxuser

src/MacOSX/audio_macosx.mm

src/Unix/autom4te.cache

src/Unix/autom4te.cache/output.0

src/Unix/autom4te.cache/requests

src/Unix/autom4te.cache/traces.0

files modified:
BasiliskII.spec

ChangeLog

INSTALL

Makefile

README

TODO

debian/TODO

debian/changelog

debian/compat

debian/control

debian/copyright

debian/menu

debian/rules

debian/watch

src/AmigaOS/clip_amiga.cpp

src/AmigaOS/prefs_amiga.cpp

src/AmigaOS/sysdeps.h

src/AmigaOS/timer_amiga.cpp

src/AmigaOS/user_strings_amiga.cpp

src/AmigaOS/user_strings_amiga.h

src/AmigaOS/video_amiga.cpp

src/BeOS/about_window.cpp

src/BeOS/about_window.h

src/BeOS/audio_beos.cpp

src/BeOS/clip_beos.cpp

src/BeOS/ether_beos.cpp

src/BeOS/extfs_beos.cpp

src/BeOS/main_beos.cpp

src/BeOS/prefs_beos.cpp

src/BeOS/prefs_editor_beos.cpp

src/BeOS/scsi_beos.cpp

src/BeOS/serial_beos.cpp

src/BeOS/sys_beos.cpp

src/BeOS/sysdeps.h

src/BeOS/timer_beos.cpp

src/BeOS/user_strings_beos.cpp

src/BeOS/user_strings_beos.h

src/BeOS/video_beos.cpp

src/BeOS/xpram_beos.cpp

src/MacOSX/0_HOW_TO_BUILD.txt

src/MacOSX/1_prepare_files.sh

src/MacOSX/BasiliskII.pbproj/project.pbxproj

src/MacOSX/Controller.h

src/MacOSX/Controller.mm

src/MacOSX/Credits.html

src/MacOSX/Emulator.h

src/MacOSX/Emulator.mm

src/MacOSX/EmulatorView.h

src/MacOSX/EmulatorView.mm

src/MacOSX/English.lproj/InfoPlist.strings

src/MacOSX/English.lproj/MainMenu.nib/classes.nib

src/MacOSX/English.lproj/MainMenu.nib/info.nib

src/MacOSX/English.lproj/MainMenu.nib/objects.nib

src/MacOSX/HowTo.html

src/MacOSX/Makefile.in

src/MacOSX/NNThread.h

src/MacOSX/NNThread.m

src/MacOSX/PrefsEditor.h

src/MacOSX/PrefsEditor.mm

src/MacOSX/ToDo.html

src/MacOSX/Versions.html

src/MacOSX/audio_defs_macosx.h

src/MacOSX/audio_macosx.cpp

src/MacOSX/configure.in

src/MacOSX/extfs_macosx.h

src/MacOSX/extfs_macosx.mm

src/MacOSX/macos_util_macosx.h

src/MacOSX/main_macosx.h

src/MacOSX/main_macosx.mm

src/MacOSX/misc_macosx.h

src/MacOSX/misc_macosx.mm

src/MacOSX/prefs_macosx.cpp

src/MacOSX/sys_darwin.cpp

src/MacOSX/sysdeps.h

src/MacOSX/video_macosx.h

src/MacOSX/video_macosx.mm

src/Unix/BasiliskII.1

src/Unix/FreeBSD/scsi_freebsd.cpp

src/Unix/FreeBSD/scsidump.cpp

src/Unix/Irix/audio_irix.cpp

src/Unix/Irix/unaligned.c

src/Unix/Linux/NetDriver/Makefile

src/Unix/Linux/NetDriver/sheep_net.c

src/Unix/Linux/scsi_linux.cpp

src/Unix/Makefile.in

src/Unix/Solaris/audio_solaris.cpp

src/Unix/acinclude.m4

src/Unix/aclocal.m4

src/Unix/asm_support.s

src/Unix/audio_oss_esd.cpp

src/Unix/clip_unix.cpp

src/Unix/config.h.in

src/Unix/configure

src/Unix/configure.ac

src/Unix/ether_unix.cpp

src/Unix/extfs_unix.cpp

src/Unix/keycodes

src/Unix/main_unix.cpp

src/Unix/posix_sem.cpp

src/Unix/prefs_editor_gtk.cpp

src/Unix/prefs_unix.cpp

src/Unix/semaphore.h

src/Unix/serial_unix.cpp

src/Unix/sigsegv.cpp

src/Unix/sigsegv.h

src/Unix/sys_unix.cpp

src/Unix/sysdeps.h

src/Unix/timer_unix.cpp

src/Unix/user_strings_unix.cpp

src/Unix/user_strings_unix.h

src/Unix/video_blit.cpp

src/Unix/video_blit.h

src/Unix/video_vosf.h

src/Unix/video_x.cpp

src/Unix/vm_alloc.cpp

src/Unix/vm_alloc.h

src/Unix/xpram_unix.cpp

src/adb.cpp

src/audio.cpp

src/cdrom.cpp

src/disk.cpp

src/dummy/audio_dummy.cpp

src/dummy/clip_dummy.cpp

src/dummy/ether_dummy.cpp

src/dummy/prefs_dummy.cpp

src/dummy/prefs_editor_dummy.cpp

src/dummy/scsi_dummy.cpp

src/dummy/serial_dummy.cpp

src/dummy/user_strings_dummy.cpp

src/dummy/xpram_dummy.cpp

src/emul_op.cpp

src/ether.cpp

src/extfs.cpp

src/include/adb.h

src/include/audio.h

src/include/audio_defs.h

src/include/cdrom.h

src/include/clip.h

src/include/debug.h

src/include/disk.h

src/include/emul_op.h

src/include/ether.h

src/include/ether_defs.h

src/include/extfs.h

src/include/extfs_defs.h

src/include/macos_util.h

src/include/main.h

src/include/prefs.h

src/include/prefs_editor.h

src/include/rom_patches.h

src/include/rsrc_patches.h

src/include/scsi.h

src/include/serial.h

src/include/serial_defs.h

src/include/slot_rom.h

src/include/sony.h

src/include/sys.h

src/include/timer.h

src/include/user_strings.h

src/include/version.h

src/include/video.h

src/include/video_defs.h

src/include/xpram.h

src/macos_util.cpp

src/main.cpp

src/native_cpu/cpu_emulation.h

src/powerrom_cpu/cpu_emulation.h

src/powerrom_cpu/powerrom_cpu.cpp

src/prefs.cpp

src/prefs_items.cpp

src/rom_patches.cpp

src/rsrc_patches.cpp

src/scsi.cpp

src/serial.cpp

src/slot_rom.cpp

src/sony.cpp

src/timer.cpp

src/uae_cpu/basilisk_glue.cpp

src/uae_cpu/build68k.c

src/uae_cpu/compiler/codegen_x86.cpp

src/uae_cpu/compiler/codegen_x86.h

src/uae_cpu/compiler/compemu.h

src/uae_cpu/compiler/compemu_fpp.cpp

src/uae_cpu/compiler/compemu_support.cpp

src/uae_cpu/compiler/flags_x86.h

src/uae_cpu/compiler/gencomp.c

src/uae_cpu/cpu_emulation.h

src/uae_cpu/fpu/core.h

src/uae_cpu/fpu/exceptions.cpp

src/uae_cpu/fpu/exceptions.h

src/uae_cpu/fpu/flags.cpp

src/uae_cpu/fpu/flags.h

src/uae_cpu/fpu/fpu.h

src/uae_cpu/fpu/fpu_ieee.h

src/uae_cpu/fpu/fpu_uae.h

src/uae_cpu/fpu/fpu_x86.cpp

src/uae_cpu/fpu/fpu_x86.h

src/uae_cpu/fpu/impl.h

src/uae_cpu/fpu/mathlib.cpp

src/uae_cpu/fpu/mathlib.h

src/uae_cpu/fpu/rounding.cpp

src/uae_cpu/fpu/rounding.h

src/uae_cpu/fpu/types.h

src/uae_cpu/gencpu.c

src/uae_cpu/m68k.h

src/uae_cpu/memory.cpp

src/uae_cpu/memory.h

src/uae_cpu/newcpu.cpp

src/uae_cpu/newcpu.h

src/uae_cpu/readcpu.cpp

src/uae_cpu/spcflags.h

src/user_strings.cpp

src/video.cpp

src/xpram.cpp

Show diffs side-by-side

added added

removed removed

src/slirp/tcp_input.c

* Redistribution and use in source and binary forms, with or without

* modification, are permitted provided that the following conditions

* are met:

* 1. Redistributions of source code must retain the above copyright

* notice, this list of conditions and the following disclaimer.

* 2. Redistributions in binary form must reproduce the above copyright

* notice, this list of conditions and the following disclaimer in the

* documentation and/or other materials provided with the distribution.

* 3. All advertising materials mentioning features or use of this software

* must display the following acknowledgement:

* This product includes software developed by the University of

* California, Berkeley and its contributors.

* 4. Neither the name of the University nor the names of its contributors

* may be used to endorse or promote products derived from this software

* without specific prior written permission.

* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

* SUCH DAMAGE.

* @(#)tcp_input.c 8.5 (Berkeley) 4/10/94

* tcp_input.c,v 1.10 1994/10/13 18:36:32 wollman Exp

* Changes and additions relating to SLiRP

* Please read the file COPYRIGHT for the

* terms and conditions of the copyright.

#include <slirp.h>

#include "ip_icmp.h"

struct socket tcb;

int tcprexmtthresh = 3;

struct socket *tcp_last_so = &tcb;

tcp_seq tcp_iss; /* tcp initial send seq # */

#define TCP_PAWS_IDLE (24 * 24 * 60 * 60 * PR_SLOWHZ)

/* for modulo comparisons of timestamps */

#define TSTMP_LT(a,b) ((int)((a)-(b)) < 0)

#define TSTMP_GEQ(a,b) ((int)((a)-(b)) >= 0)

* Insert segment ti into reassembly queue of tcp with

* control block tp. Return TH_FIN if reassembly now includes

* a segment with FIN. The macro form does the common case inline

* (segment is the next to be received on an established connection,

* and the queue is empty), avoiding linkage into and removal

* from the queue and repetition of various conversions.

* Set DELACK for segments received in order, but ack immediately

* when segments are out of order (so fast retransmit can work).

#ifdef TCP_ACK_HACK

#define TCP_REASS(tp, ti, m, so, flags) {\

if ((ti)->ti_seq == (tp)->rcv_nxt && \

(tp)->seg_next == (tcpiphdrp_32)(tp) && \

(tp)->t_state == TCPS_ESTABLISHED) {\

if (ti->ti_flags & TH_PUSH) \

tp->t_flags |= TF_ACKNOW; \

else \

tp->t_flags |= TF_DELACK; \

(tp)->rcv_nxt += (ti)->ti_len; \

flags = (ti)->ti_flags & TH_FIN; \

tcpstat.tcps_rcvpack++;\

tcpstat.tcps_rcvbyte += (ti)->ti_len;\

if (so->so_emu) { \

if (tcp_emu((so),(m))) sbappend((so), (m)); \

} else \

sbappend((so), (m)); \

/* sorwakeup(so); */ \

} else {\

(flags) = tcp_reass((tp), (ti), (m)); \

tp->t_flags |= TF_ACKNOW; \

} \

}

#else

#define TCP_REASS(tp, ti, m, so, flags) { \

if ((ti)->ti_seq == (tp)->rcv_nxt && \

(tp)->seg_next == (tcpiphdrp_32)(tp) && \

(tp)->t_state == TCPS_ESTABLISHED) { \

tp->t_flags |= TF_DELACK; \

100

(tp)->rcv_nxt += (ti)->ti_len; \

101

flags = (ti)->ti_flags & TH_FIN; \

102

tcpstat.tcps_rcvpack++;\

103

tcpstat.tcps_rcvbyte += (ti)->ti_len;\

104

if (so->so_emu) { \

105

if (tcp_emu((so),(m))) sbappend(so, (m)); \

106

} else \

107

sbappend((so), (m)); \

108

/* sorwakeup(so); */ \

109

} else { \

110

(flags) = tcp_reass((tp), (ti), (m)); \

111

tp->t_flags |= TF_ACKNOW; \

112

} \

113

}

114

#endif

115

116

int

117

tcp_reass(tp, ti, m)

118

119

120

struct mbuf *m;

121

{

122

123

struct socket *so = tp->t_socket;

124

int flags;

125

126

127

* Call with ti==0 after become established to

128

* force pre-ESTABLISHED data up to user socket.

129

130

if (ti == 0)

131

goto present;

132

133

134

* Find a segment which begins after this one does.

135

136

for (q = (struct tcpiphdr *)tp->seg_next; q != (struct tcpiphdr *)tp;

137

q = (struct tcpiphdr *)q->ti_next)

138

if (SEQ_GT(q->ti_seq, ti->ti_seq))

139

break;

140

141

142

* If there is a preceding segment, it may provide some of

143

* our data already. If so, drop the data from the incoming

144

* segment. If it provides all of our data, drop us.

145

146

if ((struct tcpiphdr *)q->ti_prev != (struct tcpiphdr *)tp) {

147

148

q = (struct tcpiphdr *)q->ti_prev;

149

/* conversion to int (in i) handles seq wraparound */

150

i = q->ti_seq + q->ti_len - ti->ti_seq;

151

if (i > 0) {

152

if (i >= ti->ti_len) {

153

tcpstat.tcps_rcvduppack++;

154

tcpstat.tcps_rcvdupbyte += ti->ti_len;

155

m_freem(m);

156

157

* Try to present any queued data

158

* at the left window edge to the user.

159

* This is needed after the 3-WHS

160

* completes.

161

162

goto present; /* ??? */

163

}

164

m_adj(m, i);

165

ti->ti_len -= i;

166

ti->ti_seq += i;

167

}

168

q = (struct tcpiphdr *)(q->ti_next);

169

}

170

tcpstat.tcps_rcvoopack++;

171

tcpstat.tcps_rcvoobyte += ti->ti_len;

172

REASS_MBUF(ti) = (mbufp_32) m; /* XXX */

173

174

175

* While we overlap succeeding segments trim them or,

176

* if they are completely covered, dequeue them.

177

178

while (q != (struct tcpiphdr *)tp) {

179

180

if (i <= 0)

181

break;

182

if (i < q->ti_len) {

183

q->ti_seq += i;

184

q->ti_len -= i;

185

m_adj((struct mbuf *) REASS_MBUF(q), i);

186

break;

187

}

188

q = (struct tcpiphdr *)q->ti_next;

189

m = (struct mbuf *) REASS_MBUF((struct tcpiphdr *)q->ti_prev);

190

remque_32((void *)(q->ti_prev));

191

m_freem(m);

192

}

193

194

195

* Stick new segment in its place.

196

197

insque_32(ti, (void *)(q->ti_prev));

198

199

present:

200

201

* Present data to user, advancing rcv_nxt through

202

* completed sequence space.

203

204

if (!TCPS_HAVEESTABLISHED(tp->t_state))

205

return (0);

206

ti = (struct tcpiphdr *) tp->seg_next;

207

if (ti == (struct tcpiphdr *)tp || ti->ti_seq != tp->rcv_nxt)

208

return (0);

209

if (tp->t_state == TCPS_SYN_RECEIVED && ti->ti_len)

210

return (0);

211

do {

212

tp->rcv_nxt += ti->ti_len;

213

flags = ti->ti_flags & TH_FIN;

214

remque_32(ti);

215

m = (struct mbuf *) REASS_MBUF(ti); /* XXX */

216

ti = (struct tcpiphdr *)ti->ti_next;

217

/* if (so->so_state & SS_FCANTRCVMORE) */

218

if (so->so_state & SS_FCANTSENDMORE)

219

m_freem(m);

220

else {

221

if (so->so_emu) {

222

if (tcp_emu(so,m)) sbappend(so, m);

223

} else

224

sbappend(so, m);

225

}

226

} while (ti != (struct tcpiphdr *)tp && ti->ti_seq == tp->rcv_nxt);

227

/* sorwakeup(so); */

228

return (flags);

229

}

230

231

232

* TCP input routine, follows pages 65-76 of the

233

* protocol specification dated September, 1981 very closely.

234

235

void

236

tcp_input(m, iphlen, inso)

237

238

int iphlen;

239

struct socket *inso;

240

{

241

struct ip save_ip, *ip;

242

243

caddr_t optp = NULL;

244

int optlen = 0;

245

int len, tlen, off;

246

247

248

struct socket *so = 0;

249

int todrop, acked, ourfinisacked, needoutput = 0;

250

/* int dropsocket = 0; */

251

int iss = 0;

252

u_long tiwin;

253

int ret;

254

/* int ts_present = 0; */

255

256

DEBUG_CALL("tcp_input");

257

DEBUG_ARGS((dfd," m = %8lx iphlen = %2d inso = %lx\n",

258

(long )m, iphlen, (long )inso ));

259

260

261

* If called with m == 0, then we're continuing the connect

262

263

if (m == NULL) {

264

so = inso;

265

266

/* Re-set a few variables */

267

tp = sototcpcb(so);

268

m = so->so_m;

269

so->so_m = 0;

270

ti = so->so_ti;

271

tiwin = ti->ti_win;

272

tiflags = ti->ti_flags;

273

274

goto cont_conn;

275

}

276

277

278

tcpstat.tcps_rcvtotal++;

279

280

* Get IP and TCP header together in first mbuf.

281

* Note: IP leaves IP header in first mbuf.

282

283

ti = mtod(m, struct tcpiphdr *);

284

if (iphlen > sizeof(struct ip )) {

285

ip_stripoptions(m, (struct mbuf *)0);

286

iphlen=sizeof(struct ip );

287

}

288

/* XXX Check if too short */

289

290

291

292

* Save a copy of the IP header in case we want restore it

293

* for sending an ICMP error message in response.

294

295

ip=mtod(m, struct ip *);

296

save_ip = *ip;

297

save_ip.ip_len+= iphlen;

298

299

300

* Checksum extended TCP header and data.

301

302

tlen = ((struct ip *)ti)->ip_len;

303

ti->ti_next = ti->ti_prev = 0;

304

ti->ti_x1 = 0;

305

ti->ti_len = htons((u_int16_t)tlen);

306

len = sizeof(struct ip ) + tlen;

307

/* keep checksum for ICMP reply

308

* ti->ti_sum = cksum(m, len);

309

* if (ti->ti_sum) { */

310

if(cksum(m, len)) {

311

tcpstat.tcps_rcvbadsum++;

312

goto drop;

313

}

314

315

316

* Check that TCP offset makes sense,

317

* pull out TCP options and adjust length. XXX

318

319

off = ti->ti_off << 2;

320

if (off < sizeof (struct tcphdr) || off > tlen) {

321

tcpstat.tcps_rcvbadoff++;

322

goto drop;

323

}

324

tlen -= off;

325

ti->ti_len = tlen;

326

if (off > sizeof (struct tcphdr)) {

327

optlen = off - sizeof (struct tcphdr);

328

optp = mtod(m, caddr_t) + sizeof (struct tcpiphdr);

329

330

331

* Do quick retrieval of timestamp options ("options

332

* prediction?"). If timestamp is the only option and it's

333

* formatted as recommended in RFC 1323 appendix A, we

334

* quickly get the values now and not bother calling

335

* tcp_dooptions(), etc.

336

337

/* if ((optlen == TCPOLEN_TSTAMP_APPA ||

338

* (optlen > TCPOLEN_TSTAMP_APPA &&

339

* optp[TCPOLEN_TSTAMP_APPA] == TCPOPT_EOL)) &&

340

* *(u_int32_t *)optp == htonl(TCPOPT_TSTAMP_HDR) &&

341

* (ti->ti_flags & TH_SYN) == 0) {

342

* ts_present = 1;

343

* ts_val = ntohl(*(u_int32_t *)(optp + 4));

344

* ts_ecr = ntohl(*(u_int32_t *)(optp + 8));

345

* optp = NULL; / * we've parsed the options * /

346

* }

347

348

}

349

tiflags = ti->ti_flags;

350

351

352

* Convert TCP protocol specific fields to host format.

353

354

NTOHL(ti->ti_seq);

355

NTOHL(ti->ti_ack);

356

NTOHS(ti->ti_win);

357

NTOHS(ti->ti_urp);

358

359

360

* Drop TCP, IP headers and TCP options.

361

362

m->m_data += sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);

363

m->m_len -= sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);

364

365

366

* Locate pcb for segment.

367

368

findso:

369

so = tcp_last_so;

370

if (so->so_fport != ti->ti_dport ||

371

so->so_lport != ti->ti_sport ||

372

so->so_laddr.s_addr != ti->ti_src.s_addr ||

373

so->so_faddr.s_addr != ti->ti_dst.s_addr) {

374

so = solookup(&tcb, ti->ti_src, ti->ti_sport,

375

ti->ti_dst, ti->ti_dport);

376

if (so)

377

tcp_last_so = so;

378

++tcpstat.tcps_socachemiss;

379

}

380

381

382

* If the state is CLOSED (i.e., TCB does not exist) then

383

* all data in the incoming segment is discarded.

384

* If the TCB exists but is in CLOSED state, it is embryonic,

385

* but should either do a listen or a connect soon.

386

387

* state == CLOSED means we've done socreate() but haven't

388

* attached it to a protocol yet...

389

390

* XXX If a TCB does not exist, and the TH_SYN flag is

391

* the only flag set, then create a session, mark it

392

* as if it was LISTENING, and continue...

393

394

if (so == 0) {

395

if ((tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) != TH_SYN)

396

goto dropwithreset;

397

398

if ((so = socreate()) == NULL)

399

goto dropwithreset;

400

if (tcp_attach(so) < 0) {

401

free(so); /* Not sofree (if it failed, it's not insqued) */

402

goto dropwithreset;

403

}

404

405

sbreserve(&so->so_snd, tcp_sndspace);

406

sbreserve(&so->so_rcv, tcp_rcvspace);

407

408

/* tcp_last_so = so; */ /* XXX ? */

409

/* tp = sototcpcb(so); */

410

411

so->so_laddr = ti->ti_src;

412

so->so_lport = ti->ti_sport;

413

so->so_faddr = ti->ti_dst;

414

so->so_fport = ti->ti_dport;

415

416

if ((so->so_iptos = tcp_tos(so)) == 0)

417

so->so_iptos = ((struct ip *)ti)->ip_tos;

418

419

tp = sototcpcb(so);

420

tp->t_state = TCPS_LISTEN;

421

}

422

423

424

* If this is a still-connecting socket, this probably

425

* a retransmit of the SYN. Whether it's a retransmit SYN

426

* or something else, we nuke it.

427

428

if (so->so_state & SS_ISFCONNECTING)

429

goto drop;

430

431

tp = sototcpcb(so);

432

433

/* XXX Should never fail */

434

if (tp == 0)

435

goto dropwithreset;

436

if (tp->t_state == TCPS_CLOSED)

437

goto drop;

438

439

/* Unscale the window into a 32-bit value. */

440

/* if ((tiflags & TH_SYN) == 0)

441

* tiwin = ti->ti_win << tp->snd_scale;

442

* else

443

444

tiwin = ti->ti_win;

445

446

447

* Segment received on connection.

448

* Reset idle time and keep-alive timer.

449

450

tp->t_idle = 0;

451

if (so_options)

452

tp->t_timer[TCPT_KEEP] = tcp_keepintvl;

453

else

454

tp->t_timer[TCPT_KEEP] = tcp_keepidle;

455

456

457

* Process options if not in LISTEN state,

458

* else do it below (after getting remote address).

459

460

if (optp && tp->t_state != TCPS_LISTEN)

461

tcp_dooptions(tp, (u_char *)optp, optlen, ti);

462

/* , */

463

/* &ts_present, &ts_val, &ts_ecr); */

464

465

466

* Header prediction: check for the two common cases

467

* of a uni-directional data xfer. If the packet has

468

* no control flags, is in-sequence, the window didn't

469

* change and we're not retransmitting, it's a

470

* candidate. If the length is zero and the ack moved

471

* forward, we're the sender side of the xfer. Just

472

* free the data acked & wake any higher level process

473

* that was blocked waiting for space. If the length

474

* is non-zero and the ack didn't move, we're the

475

* receiver side. If we're getting packets in-order

476

* (the reassembly queue is empty), add the data to

477

* the socket buffer and note that we need a delayed ack.

478

479

* XXX Some of these tests are not needed

480

* eg: the tiwin == tp->snd_wnd prevents many more

481

* predictions.. with no *real* advantage..

482

483

if (tp->t_state == TCPS_ESTABLISHED &&

484

(tiflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) == TH_ACK &&

485

/* (!ts_present || TSTMP_GEQ(ts_val, tp->ts_recent)) && */

486

ti->ti_seq == tp->rcv_nxt &&

487

tiwin && tiwin == tp->snd_wnd &&

488

tp->snd_nxt == tp->snd_max) {

489

490

* If last ACK falls within this segment's sequence numbers,

491

* record the timestamp.

492

493

/* if (ts_present && SEQ_LEQ(ti->ti_seq, tp->last_ack_sent) &&

494

* SEQ_LT(tp->last_ack_sent, ti->ti_seq + ti->ti_len)) {

495

* tp->ts_recent_age = tcp_now;

496

* tp->ts_recent = ts_val;

497

* }

498

499

if (ti->ti_len == 0) {

500

if (SEQ_GT(ti->ti_ack, tp->snd_una) &&

501

SEQ_LEQ(ti->ti_ack, tp->snd_max) &&

502

tp->snd_cwnd >= tp->snd_wnd) {

503

504

* this is a pure ack for outstanding data.

505

506

++tcpstat.tcps_predack;

507

/* if (ts_present)

508

* tcp_xmit_timer(tp, tcp_now-ts_ecr+1);

509

* else

510

*/ if (tp->t_rtt &&

511

SEQ_GT(ti->ti_ack, tp->t_rtseq))

512

tcp_xmit_timer(tp, tp->t_rtt);

513

acked = ti->ti_ack - tp->snd_una;

514

tcpstat.tcps_rcvackpack++;

515

tcpstat.tcps_rcvackbyte += acked;

516

sbdrop(&so->so_snd, acked);

517

tp->snd_una = ti->ti_ack;

518

m_freem(m);

519

520

521

* If all outstanding data are acked, stop

522

* retransmit timer, otherwise restart timer

523

* using current (possibly backed-off) value.

524

* If process is waiting for space,

525

* wakeup/selwakeup/signal. If data

526

* are ready to send, let tcp_output

527

* decide between more output or persist.

528

529

if (tp->snd_una == tp->snd_max)

530

tp->t_timer[TCPT_REXMT] = 0;

531

else if (tp->t_timer[TCPT_PERSIST] == 0)

532

tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;

533

534

535

* There's room in so_snd, sowwakup will read()

536

* from the socket if we can

537

538

/* if (so->so_snd.sb_flags & SB_NOTIFY)

539

* sowwakeup(so);

540

541

542

* This is called because sowwakeup might have

543

* put data into so_snd. Since we don't so sowwakeup,

544

* we don't need this.. XXX???

545

546

if (so->so_snd.sb_cc)

547

(void) tcp_output(tp);

548

549

return;

550

}

551

} else if (ti->ti_ack == tp->snd_una &&

552

tp->seg_next == (tcpiphdrp_32)tp &&

553

ti->ti_len <= sbspace(&so->so_rcv)) {

554

555

* this is a pure, in-sequence data packet

556

* with nothing on the reassembly queue and

557

* we have enough buffer space to take it.

558

559

++tcpstat.tcps_preddat;

560

tp->rcv_nxt += ti->ti_len;

561

tcpstat.tcps_rcvpack++;

562

tcpstat.tcps_rcvbyte += ti->ti_len;

563

564

* Add data to socket buffer.

565

566

if (so->so_emu) {

567

if (tcp_emu(so,m)) sbappend(so, m);

568

} else

569

sbappend(so, m);

570

571

572

* XXX This is called when data arrives. Later, check

573

* if we can actually write() to the socket

574

* XXX Need to check? It's be NON_BLOCKING

575

576

/* sorwakeup(so); */

577

578

579

* If this is a short packet, then ACK now - with Nagel

580

* congestion avoidance sender won't send more until

581

* he gets an ACK.

582

583

* It is better to not delay acks at all to maximize

584

* TCP throughput. See RFC 2581.

585

586

tp->t_flags |= TF_ACKNOW;

587

tcp_output(tp);

588

return;

589

}

590

} /* header prediction */

591

592

* Calculate amount of space in receive window,

593

* and then do TCP input processing.

594

* Receive window is amount of space in rcv queue,

595

* but not less than advertised window.

596

597

{ int win;

598

win = sbspace(&so->so_rcv);

599

if (win < 0)

600

win = 0;

601

tp->rcv_wnd = max(win, (int)(tp->rcv_adv - tp->rcv_nxt));

602

}

603

604

switch (tp->t_state) {

605

606

607

* If the state is LISTEN then ignore segment if it contains an RST.

608

* If the segment contains an ACK then it is bad and send a RST.

609

* If it does not contain a SYN then it is not interesting; drop it.

610

* Don't bother responding if the destination was a broadcast.

611

* Otherwise initialize tp->rcv_nxt, and tp->irs, select an initial

612

* tp->iss, and send a segment:

613

* <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK>

614

* Also initialize tp->snd_nxt to tp->iss+1 and tp->snd_una to tp->iss.

615

* Fill in remote peer address fields if not previously specified.

616

* Enter SYN_RECEIVED state, and process any other fields of this

617

* segment in this state.

618

619

case TCPS_LISTEN: {

620

621

if (tiflags & TH_RST)

622

goto drop;

623

if (tiflags & TH_ACK)

624

goto dropwithreset;

625

if ((tiflags & TH_SYN) == 0)

626

goto drop;

627

628

629

* This has way too many gotos...

630

* But a bit of spaghetti code never hurt anybody :)

631

632

633

634

* If this is destined for the control address, then flag to

635

* tcp_ctl once connected, otherwise connect

636

637

if ((so->so_faddr.s_addr&htonl(0xffffff00)) == special_addr.s_addr) {

638

int lastbyte=ntohl(so->so_faddr.s_addr) & 0xff;

639

if (lastbyte!=CTL_ALIAS && lastbyte!=CTL_DNS) {

640

#if 0

641

if(lastbyte==CTL_CMD || lastbyte==CTL_EXEC) {

642

/* Command or exec adress */

643

so->so_state |= SS_CTL;

644

} else

645

#endif

646

{

647

/* May be an add exec */

648

struct ex_list *ex_ptr;

649

for(ex_ptr = exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {

650

if(ex_ptr->ex_fport == so->so_fport &&

651

lastbyte == ex_ptr->ex_addr) {

652

so->so_state |= SS_CTL;

653

break;

654

}

655

}

656

}

657

if(so->so_state & SS_CTL) goto cont_input;

658

}

659

/* CTL_ALIAS: Do nothing, tcp_fconnect will be called on it */

660

}

661

662

if (so->so_emu & EMU_NOCONNECT) {

663

so->so_emu &= ~EMU_NOCONNECT;

664

goto cont_input;

665

}

666

667

if((tcp_fconnect(so) == -1) && (errno != EINPROGRESS) && (errno != EWOULDBLOCK)) {

668

u_char code=ICMP_UNREACH_NET;

669

DEBUG_MISC((dfd," tcp fconnect errno = %d-%s\n",

670

errno,strerror(errno)));

671

if(errno == ECONNREFUSED) {

672

/* ACK the SYN, send RST to refuse the connection */

673

tcp_respond(tp, ti, m, ti->ti_seq+1, (tcp_seq)0,

674

TH_RST|TH_ACK);

675

} else {

676

if(errno == EHOSTUNREACH) code=ICMP_UNREACH_HOST;

677

HTONL(ti->ti_seq); /* restore tcp header */

678

HTONL(ti->ti_ack);

679

HTONS(ti->ti_win);

680

HTONS(ti->ti_urp);

681

m->m_data -= sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);

682

m->m_len += sizeof(struct tcpiphdr)+off-sizeof(struct tcphdr);

683

*ip=save_ip;

684

icmp_error(m, ICMP_UNREACH,code, 0,strerror(errno));

685

}

686

tp = tcp_close(tp);

687

m_free(m);

688

} else {

689

690

* Haven't connected yet, save the current mbuf

691

* and ti, and return

692

* XXX Some OS's don't tell us whether the connect()

693

* succeeded or not. So we must time it out.

694

695

so->so_m = m;

696

so->so_ti = ti;

697

tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;

698

tp->t_state = TCPS_SYN_RECEIVED;

699

}

700

return;

701

702

cont_conn:

703

/* m==NULL

704

* Check if the connect succeeded

705

706

if (so->so_state & SS_NOFDREF) {

707

tp = tcp_close(tp);

708

goto dropwithreset;

709

}

710

cont_input:

711

tcp_template(tp);

712

713

if (optp)

714

tcp_dooptions(tp, (u_char *)optp, optlen, ti);

715

/* , */

716

/* &ts_present, &ts_val, &ts_ecr); */

717

718

if (iss)

719

tp->iss = iss;

720

else

721

tp->iss = tcp_iss;

722

tcp_iss += TCP_ISSINCR/2;

723

tp->irs = ti->ti_seq;

724

tcp_sendseqinit(tp);

725

tcp_rcvseqinit(tp);

726

tp->t_flags |= TF_ACKNOW;

727

tp->t_state = TCPS_SYN_RECEIVED;

728

tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;

729

tcpstat.tcps_accepts++;

730

goto trimthenstep6;

731

} /* case TCPS_LISTEN */

732

733

734

* If the state is SYN_SENT:

735

* if seg contains an ACK, but not for our SYN, drop the input.

736

* if seg contains a RST, then drop the connection.

737

* if seg does not contain SYN, then drop it.

738

* Otherwise this is an acceptable SYN segment

739

* initialize tp->rcv_nxt and tp->irs

740

* if seg contains ack then advance tp->snd_una

741

* if SYN has been acked change to ESTABLISHED else SYN_RCVD state

742

* arrange for segment to be acked (eventually)

743

* continue processing rest of data/controls, beginning with URG

744

745

case TCPS_SYN_SENT:

746

if ((tiflags & TH_ACK) &&

747

(SEQ_LEQ(ti->ti_ack, tp->iss) ||

748

SEQ_GT(ti->ti_ack, tp->snd_max)))

749

goto dropwithreset;

750

751

if (tiflags & TH_RST) {

752

if (tiflags & TH_ACK)

753

tp = tcp_drop(tp,0); /* XXX Check t_softerror! */

754

goto drop;

755

}

756

757

if ((tiflags & TH_SYN) == 0)

758

goto drop;

759

if (tiflags & TH_ACK) {

760

tp->snd_una = ti->ti_ack;

761

if (SEQ_LT(tp->snd_nxt, tp->snd_una))

762

tp->snd_nxt = tp->snd_una;

763

}

764

765

tp->t_timer[TCPT_REXMT] = 0;

766

tp->irs = ti->ti_seq;

767

tcp_rcvseqinit(tp);

768

tp->t_flags |= TF_ACKNOW;

769

if (tiflags & TH_ACK && SEQ_GT(tp->snd_una, tp->iss)) {

770

tcpstat.tcps_connects++;

771

soisfconnected(so);

772

tp->t_state = TCPS_ESTABLISHED;

773

774

/* Do window scaling on this connection? */

775

/* if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) ==

776

* (TF_RCVD_SCALE|TF_REQ_SCALE)) {

777

* tp->snd_scale = tp->requested_s_scale;

778

* tp->rcv_scale = tp->request_r_scale;

779

* }

780

781

(void) tcp_reass(tp, (struct tcpiphdr *)0,

782

(struct mbuf *)0);

783

784

* if we didn't have to retransmit the SYN,

785

* use its rtt as our initial srtt & rtt var.

786

787

if (tp->t_rtt)

788

tcp_xmit_timer(tp, tp->t_rtt);

789

} else

790

tp->t_state = TCPS_SYN_RECEIVED;

791

792

trimthenstep6:

793

794

* Advance ti->ti_seq to correspond to first data byte.

795

* If data, trim to stay within window,

796

* dropping FIN if necessary.

797

798

ti->ti_seq++;

799

if (ti->ti_len > tp->rcv_wnd) {

800

todrop = ti->ti_len - tp->rcv_wnd;

801

m_adj(m, -todrop);

802

ti->ti_len = tp->rcv_wnd;

803

tiflags &= ~TH_FIN;

804

tcpstat.tcps_rcvpackafterwin++;

805

tcpstat.tcps_rcvbyteafterwin += todrop;

806

}

807

tp->snd_wl1 = ti->ti_seq - 1;

808

tp->rcv_up = ti->ti_seq;

809

goto step6;

810

} /* switch tp->t_state */

811

812

* States other than LISTEN or SYN_SENT.

813

* First check timestamp, if present.

814

* Then check that at least some bytes of segment are within

815

* receive window. If segment begins before rcv_nxt,

816

* drop leading data (and SYN); if nothing left, just ack.

817

818

* RFC 1323 PAWS: If we have a timestamp reply on this segment

819

* and it's less than ts_recent, drop it.

820

821

/* if (ts_present && (tiflags & TH_RST) == 0 && tp->ts_recent &&

822

* TSTMP_LT(ts_val, tp->ts_recent)) {

823

824

*/ /* Check to see if ts_recent is over 24 days old. */

825

/* if ((int)(tcp_now - tp->ts_recent_age) > TCP_PAWS_IDLE) {

826

*/ /*

827

* * Invalidate ts_recent. If this segment updates

828

* * ts_recent, the age will be reset later and ts_recent

829

* * will get a valid value. If it does not, setting

830

* * ts_recent to zero will at least satisfy the

831

* * requirement that zero be placed in the timestamp

832

* * echo reply when ts_recent isn't valid. The

833

* * age isn't reset until we get a valid ts_recent

834

* * because we don't want out-of-order segments to be

835

* * dropped when ts_recent is old.

836

* */

837

/* tp->ts_recent = 0;

838

* } else {

839

* tcpstat.tcps_rcvduppack++;

840

* tcpstat.tcps_rcvdupbyte += ti->ti_len;

841

* tcpstat.tcps_pawsdrop++;

842

* goto dropafterack;

843

* }

844

* }

845

846

847

todrop = tp->rcv_nxt - ti->ti_seq;

848

if (todrop > 0) {

849

if (tiflags & TH_SYN) {

850

tiflags &= ~TH_SYN;

851

ti->ti_seq++;

852

if (ti->ti_urp > 1)

853

ti->ti_urp--;

854

else

855

tiflags &= ~TH_URG;

856

todrop--;

857

}

858

859

* Following if statement from Stevens, vol. 2, p. 960.

860

861

if (todrop > ti->ti_len

862

|| (todrop == ti->ti_len && (tiflags & TH_FIN) == 0)) {

863

864

* Any valid FIN must be to the left of the window.

865

* At this point the FIN must be a duplicate or out

866

* of sequence; drop it.

867

868

tiflags &= ~TH_FIN;

869

870

871

* Send an ACK to resynchronize and drop any data.

872

* But keep on processing for RST or ACK.

873

874

tp->t_flags |= TF_ACKNOW;

875

todrop = ti->ti_len;

876

tcpstat.tcps_rcvduppack++;

877

tcpstat.tcps_rcvdupbyte += todrop;

878

} else {

879

tcpstat.tcps_rcvpartduppack++;

880

tcpstat.tcps_rcvpartdupbyte += todrop;

881

}

882

m_adj(m, todrop);

883

ti->ti_seq += todrop;

884

ti->ti_len -= todrop;

885

if (ti->ti_urp > todrop)

886

ti->ti_urp -= todrop;

887

else {

888

tiflags &= ~TH_URG;

889

ti->ti_urp = 0;

890

}

891

}

892

893

* If new data are received on a connection after the

894

* user processes are gone, then RST the other end.

895

896

if ((so->so_state & SS_NOFDREF) &&

897

tp->t_state > TCPS_CLOSE_WAIT && ti->ti_len) {

898

tp = tcp_close(tp);

899

tcpstat.tcps_rcvafterclose++;

900

goto dropwithreset;

901

}

902

903

904

* If segment ends after window, drop trailing data

905

* (and PUSH and FIN); if nothing left, just ACK.

906

907

todrop = (ti->ti_seq+ti->ti_len) - (tp->rcv_nxt+tp->rcv_wnd);

908

if (todrop > 0) {

909

tcpstat.tcps_rcvpackafterwin++;

910

if (todrop >= ti->ti_len) {

911

tcpstat.tcps_rcvbyteafterwin += ti->ti_len;

912

913

* If a new connection request is received

914

* while in TIME_WAIT, drop the old connection

915

* and start over if the sequence numbers

916

* are above the previous ones.

917

918

if (tiflags & TH_SYN &&

919

tp->t_state == TCPS_TIME_WAIT &&

920

SEQ_GT(ti->ti_seq, tp->rcv_nxt)) {

921

iss = tp->rcv_nxt + TCP_ISSINCR;

922

tp = tcp_close(tp);

923

goto findso;

924

}

925

926

* If window is closed can only take segments at

927

* window edge, and have to drop data and PUSH from

928

* incoming segments. Continue processing, but

929

* remember to ack. Otherwise, drop segment

930

* and ack.

931

932

if (tp->rcv_wnd == 0 && ti->ti_seq == tp->rcv_nxt) {

933

tp->t_flags |= TF_ACKNOW;

934

tcpstat.tcps_rcvwinprobe++;

935

} else

936

goto dropafterack;

937

} else

938

tcpstat.tcps_rcvbyteafterwin += todrop;

939

m_adj(m, -todrop);

940

ti->ti_len -= todrop;

941

tiflags &= ~(TH_PUSH|TH_FIN);

942

}

943

944

945

* If last ACK falls within this segment's sequence numbers,

946

* record its timestamp.

947

948

/* if (ts_present && SEQ_LEQ(ti->ti_seq, tp->last_ack_sent) &&

949

* SEQ_LT(tp->last_ack_sent, ti->ti_seq + ti->ti_len +

950

* ((tiflags & (TH_SYN|TH_FIN)) != 0))) {

951

* tp->ts_recent_age = tcp_now;

952

* tp->ts_recent = ts_val;

953

* }

954

955

956

957

* If the RST bit is set examine the state:

958

* SYN_RECEIVED STATE:

959

* If passive open, return to LISTEN state.

960

* If active open, inform user that connection was refused.

961

* ESTABLISHED, FIN_WAIT_1, FIN_WAIT2, CLOSE_WAIT STATES:

962

* Inform user that connection was reset, and close tcb.

963

* CLOSING, LAST_ACK, TIME_WAIT STATES

964

* Close the tcb.

965

966

if (tiflags&TH_RST) switch (tp->t_state) {

967

968

case TCPS_SYN_RECEIVED:

969

/* so->so_error = ECONNREFUSED; */

970

goto close;

971

972

case TCPS_ESTABLISHED:

973

case TCPS_FIN_WAIT_1:

974

case TCPS_FIN_WAIT_2:

975

case TCPS_CLOSE_WAIT:

976

/* so->so_error = ECONNRESET; */

977

close:

978

tp->t_state = TCPS_CLOSED;

979

tcpstat.tcps_drops++;

980

tp = tcp_close(tp);

981

goto drop;

982

983

case TCPS_CLOSING:

984

case TCPS_LAST_ACK:

985

case TCPS_TIME_WAIT:

986

tp = tcp_close(tp);

987

goto drop;

988

}

989

990

991

* If a SYN is in the window, then this is an

992

* error and we send an RST and drop the connection.

993

994

if (tiflags & TH_SYN) {

995

tp = tcp_drop(tp,0);

996

goto dropwithreset;

997

}

998

999

1000

* If the ACK bit is off we drop the segment and return.

1001

1002

if ((tiflags & TH_ACK) == 0) goto drop;

1003

1004

1005

* Ack processing.

1006

1007

switch (tp->t_state) {

1008

1009

* In SYN_RECEIVED state if the ack ACKs our SYN then enter

1010

* ESTABLISHED state and continue processing, otherwise

1011

* send an RST. una<=ack<=max

1012

1013

case TCPS_SYN_RECEIVED:

1014

1015

if (SEQ_GT(tp->snd_una, ti->ti_ack) ||

1016

SEQ_GT(ti->ti_ack, tp->snd_max))

1017

goto dropwithreset;

1018

tcpstat.tcps_connects++;

1019

tp->t_state = TCPS_ESTABLISHED;

1020

1021

* The sent SYN is ack'ed with our sequence number +1

1022

* The first data byte already in the buffer will get

1023

* lost if no correction is made. This is only needed for

1024

* SS_CTL since the buffer is empty otherwise.

1025

* tp->snd_una++; or:

1026

1027

tp->snd_una=ti->ti_ack;

1028

if (so->so_state & SS_CTL) {

1029

/* So tcp_ctl reports the right state */

1030

ret = tcp_ctl(so);

1031

if (ret == 1) {

1032

soisfconnected(so);

1033

so->so_state &= ~SS_CTL; /* success XXX */

1034

} else if (ret == 2) {

1035

so->so_state = SS_NOFDREF; /* CTL_CMD */

1036

} else {

1037

needoutput = 1;

1038

tp->t_state = TCPS_FIN_WAIT_1;

1039

}

1040

} else {

1041

soisfconnected(so);

1042

}

1043

1044

/* Do window scaling? */

1045

/* if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) ==

1046

* (TF_RCVD_SCALE|TF_REQ_SCALE)) {

1047

* tp->snd_scale = tp->requested_s_scale;

1048

* tp->rcv_scale = tp->request_r_scale;

1049

* }

1050

1051

(void) tcp_reass(tp, (struct tcpiphdr *)0, (struct mbuf *)0);

1052

tp->snd_wl1 = ti->ti_seq - 1;

1053

/* Avoid ack processing; snd_una==ti_ack => dup ack */

1054

goto synrx_to_est;

1055

/* fall into ... */

1056

1057

1058

* In ESTABLISHED state: drop duplicate ACKs; ACK out of range

1059

* ACKs. If the ack is in the range

1060

* tp->snd_una < ti->ti_ack <= tp->snd_max

1061

* then advance tp->snd_una to ti->ti_ack and drop

1062

* data from the retransmission queue. If this ACK reflects

1063

* more up to date window information we update our window information.

1064

1065

case TCPS_ESTABLISHED:

1066

case TCPS_FIN_WAIT_1:

1067

case TCPS_FIN_WAIT_2:

1068

case TCPS_CLOSE_WAIT:

1069

case TCPS_CLOSING:

1070

case TCPS_LAST_ACK:

1071

case TCPS_TIME_WAIT:

1072

1073

if (SEQ_LEQ(ti->ti_ack, tp->snd_una)) {

1074

if (ti->ti_len == 0 && tiwin == tp->snd_wnd) {

1075

tcpstat.tcps_rcvdupack++;

1076

DEBUG_MISC((dfd," dup ack m = %lx so = %lx \n",

1077

(long )m, (long )so));

1078

1079

* If we have outstanding data (other than

1080

* a window probe), this is a completely

1081

* duplicate ack (ie, window info didn't

1082

* change), the ack is the biggest we've

1083

* seen and we've seen exactly our rexmt

1084

* threshold of them, assume a packet

1085

* has been dropped and retransmit it.

1086

* Kludge snd_nxt & the congestion

1087

* window so we send only this one

1088

* packet.

1089

1090

* We know we're losing at the current

1091

* window size so do congestion avoidance

1092

* (set ssthresh to half the current window

1093

* and pull our congestion window back to

1094

* the new ssthresh).

1095

1096

* Dup acks mean that packets have left the

1097

* network (they're now cached at the receiver)

1098

* so bump cwnd by the amount in the receiver

1099

* to keep a constant cwnd packets in the

1100

* network.

1101

1102

if (tp->t_timer[TCPT_REXMT] == 0 ||

1103

ti->ti_ack != tp->snd_una)

1104

tp->t_dupacks = 0;

1105

else if (++tp->t_dupacks == tcprexmtthresh) {

1106

tcp_seq onxt = tp->snd_nxt;

1107

u_int win =

1108

min(tp->snd_wnd, tp->snd_cwnd) / 2 /

1109

tp->t_maxseg;

1110

1111

if (win < 2)

1112

win = 2;

1113

tp->snd_ssthresh = win * tp->t_maxseg;

1114

tp->t_timer[TCPT_REXMT] = 0;

1115

tp->t_rtt = 0;

1116

tp->snd_nxt = ti->ti_ack;

1117

tp->snd_cwnd = tp->t_maxseg;

1118

(void) tcp_output(tp);

1119

tp->snd_cwnd = tp->snd_ssthresh +

1120

tp->t_maxseg * tp->t_dupacks;

1121

if (SEQ_GT(onxt, tp->snd_nxt))

1122

tp->snd_nxt = onxt;

1123

goto drop;

1124

} else if (tp->t_dupacks > tcprexmtthresh) {

1125

tp->snd_cwnd += tp->t_maxseg;

1126

(void) tcp_output(tp);

1127

goto drop;

1128

}

1129

} else

1130

tp->t_dupacks = 0;

1131

break;

1132

}

1133

synrx_to_est:

1134

1135

* If the congestion window was inflated to account

1136

* for the other side's cached packets, retract it.

1137

1138

if (tp->t_dupacks > tcprexmtthresh &&

1139

tp->snd_cwnd > tp->snd_ssthresh)

1140

tp->snd_cwnd = tp->snd_ssthresh;

1141

tp->t_dupacks = 0;

1142

if (SEQ_GT(ti->ti_ack, tp->snd_max)) {

1143

tcpstat.tcps_rcvacktoomuch++;

1144

goto dropafterack;

1145

}

1146

acked = ti->ti_ack - tp->snd_una;

1147

tcpstat.tcps_rcvackpack++;

1148

tcpstat.tcps_rcvackbyte += acked;

1149

1150

1151

* If we have a timestamp reply, update smoothed

1152

* round trip time. If no timestamp is present but

1153

* transmit timer is running and timed sequence

1154

* number was acked, update smoothed round trip time.

1155

* Since we now have an rtt measurement, cancel the

1156

* timer backoff (cf., Phil Karn's retransmit alg.).

1157

* Recompute the initial retransmit timer.

1158

1159

/* if (ts_present)

1160

* tcp_xmit_timer(tp, tcp_now-ts_ecr+1);

1161

* else

1162

1163

if (tp->t_rtt && SEQ_GT(ti->ti_ack, tp->t_rtseq))

1164

tcp_xmit_timer(tp,tp->t_rtt);

1165

1166

1167

* If all outstanding data is acked, stop retransmit

1168

* timer and remember to restart (more output or persist).

1169

* If there is more data to be acked, restart retransmit

1170

* timer, using current (possibly backed-off) value.

1171

1172

if (ti->ti_ack == tp->snd_max) {

1173

tp->t_timer[TCPT_REXMT] = 0;

1174

needoutput = 1;

1175

} else if (tp->t_timer[TCPT_PERSIST] == 0)

1176

tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;

1177

1178

* When new data is acked, open the congestion window.

1179

* If the window gives us less than ssthresh packets

1180

* in flight, open exponentially (maxseg per packet).

1181

* Otherwise open linearly: maxseg per window

1182

* (maxseg^2 / cwnd per packet).

1183

1184

{

1185

1186

1187

1188

if (cw > tp->snd_ssthresh)

1189

incr = incr * incr / cw;

1190

tp->snd_cwnd = min(cw + incr, TCP_MAXWIN<<tp->snd_scale);

1191

}

1192

if (acked > so->so_snd.sb_cc) {

1193

tp->snd_wnd -= so->so_snd.sb_cc;

1194

sbdrop(&so->so_snd, (int )so->so_snd.sb_cc);

1195

ourfinisacked = 1;

1196

} else {

1197

sbdrop(&so->so_snd, acked);

1198

tp->snd_wnd -= acked;

1199

ourfinisacked = 0;

1200

}

1201

1202

* XXX sowwakup is called when data is acked and there's room for

1203

* for more data... it should read() the socket

1204

1205

/* if (so->so_snd.sb_flags & SB_NOTIFY)

1206

* sowwakeup(so);

1207

1208

tp->snd_una = ti->ti_ack;

1209

if (SEQ_LT(tp->snd_nxt, tp->snd_una))

1210

tp->snd_nxt = tp->snd_una;

1211

1212

switch (tp->t_state) {

1213

1214

1215

* In FIN_WAIT_1 STATE in addition to the processing

1216

* for the ESTABLISHED state if our FIN is now acknowledged

1217

* then enter FIN_WAIT_2.

1218

1219

case TCPS_FIN_WAIT_1:

1220

if (ourfinisacked) {

1221

1222

* If we can't receive any more

1223

* data, then closing user can proceed.

1224

* Starting the timer is contrary to the

1225

* specification, but if we don't get a FIN

1226

* we'll hang forever.

1227

1228

if (so->so_state & SS_FCANTRCVMORE) {

1229

soisfdisconnected(so);

1230

tp->t_timer[TCPT_2MSL] = tcp_maxidle;

1231

}

1232

tp->t_state = TCPS_FIN_WAIT_2;

1233

}

1234

break;

1235

1236

1237

* In CLOSING STATE in addition to the processing for

1238

* the ESTABLISHED state if the ACK acknowledges our FIN

1239

* then enter the TIME-WAIT state, otherwise ignore

1240

* the segment.

1241

1242

case TCPS_CLOSING:

1243

if (ourfinisacked) {

1244

tp->t_state = TCPS_TIME_WAIT;

1245

tcp_canceltimers(tp);

1246

tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;

1247

soisfdisconnected(so);

1248

}

1249

break;

1250

1251

1252

* In LAST_ACK, we may still be waiting for data to drain

1253

* and/or to be acked, as well as for the ack of our FIN.

1254

* If our FIN is now acknowledged, delete the TCB,

1255

* enter the closed state and return.

1256

1257

case TCPS_LAST_ACK:

1258

if (ourfinisacked) {

1259

tp = tcp_close(tp);

1260

goto drop;

1261

}

1262

break;

1263

1264

1265

* In TIME_WAIT state the only thing that should arrive

1266

* is a retransmission of the remote FIN. Acknowledge

1267

* it and restart the finack timer.

1268

1269

case TCPS_TIME_WAIT:

1270

tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;

1271

goto dropafterack;

1272

}

1273

} /* switch(tp->t_state) */

1274

1275

step6:

1276

1277

* Update window information.

1278

* Don't look at window if no ACK: TAC's send garbage on first SYN.

1279

1280

if ((tiflags & TH_ACK) &&

1281

(SEQ_LT(tp->snd_wl1, ti->ti_seq) ||

1282

(tp->snd_wl1 == ti->ti_seq && (SEQ_LT(tp->snd_wl2, ti->ti_ack) ||

1283

(tp->snd_wl2 == ti->ti_ack && tiwin > tp->snd_wnd))))) {

1284

/* keep track of pure window updates */

1285

if (ti->ti_len == 0 &&

1286

tp->snd_wl2 == ti->ti_ack && tiwin > tp->snd_wnd)

1287

tcpstat.tcps_rcvwinupd++;

1288

tp->snd_wnd = tiwin;

1289

tp->snd_wl1 = ti->ti_seq;

1290

tp->snd_wl2 = ti->ti_ack;

1291

if (tp->snd_wnd > tp->max_sndwnd)

1292

tp->max_sndwnd = tp->snd_wnd;

1293

needoutput = 1;

1294

}

1295

1296

1297

* Process segments with URG.

1298

1299

if ((tiflags & TH_URG) && ti->ti_urp &&

1300

TCPS_HAVERCVDFIN(tp->t_state) == 0) {

1301

1302

* This is a kludge, but if we receive and accept

1303

* random urgent pointers, we'll crash in

1304

* soreceive. It's hard to imagine someone

1305

* actually wanting to send this much urgent data.

1306

1307

if (ti->ti_urp + so->so_rcv.sb_cc > so->so_rcv.sb_datalen) {

1308

ti->ti_urp = 0;

1309

tiflags &= ~TH_URG;

1310

goto dodata;

1311

}

1312

1313

* If this segment advances the known urgent pointer,

1314

* then mark the data stream. This should not happen

1315

* in CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since

1316

* a FIN has been received from the remote side.

1317

* In these states we ignore the URG.

1318

1319

* According to RFC961 (Assigned Protocols),

1320

* the urgent pointer points to the last octet

1321

* of urgent data. We continue, however,

1322

* to consider it to indicate the first octet

1323

* of data past the urgent section as the original

1324

* spec states (in one of two places).

1325

1326

if (SEQ_GT(ti->ti_seq+ti->ti_urp, tp->rcv_up)) {

1327

tp->rcv_up = ti->ti_seq + ti->ti_urp;

1328

so->so_urgc = so->so_rcv.sb_cc +

1329

(tp->rcv_up - tp->rcv_nxt); /* -1; */

1330

tp->rcv_up = ti->ti_seq + ti->ti_urp;

1331

1332

}

1333

} else

1334

1335

* If no out of band data is expected,

1336

* pull receive urgent pointer along

1337

* with the receive window.

1338

1339

if (SEQ_GT(tp->rcv_nxt, tp->rcv_up))

1340

tp->rcv_up = tp->rcv_nxt;

1341

dodata:

1342

1343

1344

* Process the segment text, merging it into the TCP sequencing queue,

1345

* and arranging for acknowledgment of receipt if necessary.

1346

* This process logically involves adjusting tp->rcv_wnd as data

1347

* is presented to the user (this happens in tcp_usrreq.c,

1348

* case PRU_RCVD). If a FIN has already been received on this

1349

* connection then we just ignore the text.

1350

1351

if ((ti->ti_len || (tiflags&TH_FIN)) &&

1352

TCPS_HAVERCVDFIN(tp->t_state) == 0) {

1353

TCP_REASS(tp, ti, m, so, tiflags);

1354

1355

* Note the amount of data that peer has sent into

1356

* our window, in order to estimate the sender's

1357

* buffer size.

1358

1359

len = so->so_rcv.sb_datalen - (tp->rcv_adv - tp->rcv_nxt);

1360

} else {

1361

m_free(m);

1362

tiflags &= ~TH_FIN;

1363

}

1364

1365

1366

* If FIN is received ACK the FIN and let the user know

1367

* that the connection is closing.

1368

1369

if (tiflags & TH_FIN) {

1370

if (TCPS_HAVERCVDFIN(tp->t_state) == 0) {

1371

1372

* If we receive a FIN we can't send more data,

1373

* set it SS_FDRAIN

1374

* Shutdown the socket if there is no rx data in the

1375

* buffer.

1376

* soread() is called on completion of shutdown() and

1377

* will got to TCPS_LAST_ACK, and use tcp_output()

1378

* to send the FIN.

1379

1380

/* sofcantrcvmore(so); */

1381

sofwdrain(so);

1382

1383

tp->t_flags |= TF_ACKNOW;

1384

tp->rcv_nxt++;

1385

}

1386

switch (tp->t_state) {

1387

1388

1389

* In SYN_RECEIVED and ESTABLISHED STATES

1390

* enter the CLOSE_WAIT state.

1391

1392

case TCPS_SYN_RECEIVED:

1393

case TCPS_ESTABLISHED:

1394

if(so->so_emu == EMU_CTL) /* no shutdown on socket */

1395

tp->t_state = TCPS_LAST_ACK;

1396

else

1397

tp->t_state = TCPS_CLOSE_WAIT;

1398

break;

1399

1400

1401

* If still in FIN_WAIT_1 STATE FIN has not been acked so

1402

* enter the CLOSING state.

1403

1404

case TCPS_FIN_WAIT_1:

1405

tp->t_state = TCPS_CLOSING;

1406

break;

1407

1408

1409

* In FIN_WAIT_2 state enter the TIME_WAIT state,

1410

* starting the time-wait timer, turning off the other

1411

* standard timers.

1412

1413

case TCPS_FIN_WAIT_2:

1414

tp->t_state = TCPS_TIME_WAIT;

1415

tcp_canceltimers(tp);

1416

tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;

1417

soisfdisconnected(so);

1418

break;

1419

1420

1421

* In TIME_WAIT state restart the 2 MSL time_wait timer.

1422

1423

case TCPS_TIME_WAIT:

1424

tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;

1425

break;

1426

}

1427

}

1428

1429

1430

* If this is a small packet, then ACK now - with Nagel

1431

* congestion avoidance sender won't send more until

1432

* he gets an ACK.

1433

1434

* See above.

1435

1436

/* if (ti->ti_len && (unsigned)ti->ti_len < tp->t_maxseg) {

1437

1438

/* if ((ti->ti_len && (unsigned)ti->ti_len < tp->t_maxseg &&

1439

* (so->so_iptos & IPTOS_LOWDELAY) == 0) ||

1440

* ((so->so_iptos & IPTOS_LOWDELAY) &&

1441

* ((struct tcpiphdr_2 *)ti)->first_char == (char)27)) {

1442

1443

if (ti->ti_len && (unsigned)ti->ti_len <= 5 &&

1444

((struct tcpiphdr_2 *)ti)->first_char == (char)27) {

1445

tp->t_flags |= TF_ACKNOW;

1446

}

1447

1448

1449

* Return any desired output.

1450

1451

if (needoutput || (tp->t_flags & TF_ACKNOW)) {

1452

(void) tcp_output(tp);

1453

}

1454

return;

1455

1456

dropafterack:

1457

1458

* Generate an ACK dropping incoming segment if it occupies

1459

* sequence space, where the ACK reflects our state.

1460

1461

if (tiflags & TH_RST)

1462

goto drop;

1463

m_freem(m);

1464

tp->t_flags |= TF_ACKNOW;

1465

(void) tcp_output(tp);

1466

return;

1467

1468

dropwithreset:

1469

/* reuses m if m!=NULL, m_free() unnecessary */

1470

if (tiflags & TH_ACK)

1471

tcp_respond(tp, ti, m, (tcp_seq)0, ti->ti_ack, TH_RST);

1472

else {

1473

if (tiflags & TH_SYN) ti->ti_len++;

1474

tcp_respond(tp, ti, m, ti->ti_seq+ti->ti_len, (tcp_seq)0,

1475

TH_RST|TH_ACK);

1476

}

1477

1478

return;

1479

1480

drop:

1481

1482

* Drop space held by incoming segment and return.

1483

1484

m_free(m);

1485

1486

return;

1487

}

1488

1489

/* , ts_present, ts_val, ts_ecr) */

1490

/* int *ts_present;

1491

* u_int32_t *ts_val, *ts_ecr;

1492

1493

void

1494

tcp_dooptions(tp, cp, cnt, ti)

1495

struct tcpcb *tp;

1496

u_char *cp;

1497

int cnt;

1498

struct tcpiphdr *ti;

1499

{

1500

u_int16_t mss;

1501

int opt, optlen;

1502

1503

DEBUG_CALL("tcp_dooptions");

1504

DEBUG_ARGS((dfd," tp = %lx cnt=%i \n", (long )tp, cnt));

1505

1506

for (; cnt > 0; cnt -= optlen, cp += optlen) {

1507

opt = cp[0];

1508

if (opt == TCPOPT_EOL)

1509

break;

1510

if (opt == TCPOPT_NOP)

1511

optlen = 1;

1512

else {

1513

optlen = cp[1];

1514

if (optlen <= 0)

1515

break;

1516

}

1517

switch (opt) {

1518

1519

default:

1520

continue;

1521

1522

case TCPOPT_MAXSEG:

1523

if (optlen != TCPOLEN_MAXSEG)

1524

continue;

1525

if (!(ti->ti_flags & TH_SYN))

1526

continue;

1527

memcpy((char *) &mss, (char *) cp + 2, sizeof(mss));

1528

NTOHS(mss);

1529

(void) tcp_mss(tp, mss); /* sets t_maxseg */

1530

break;

1531

1532

/* case TCPOPT_WINDOW:

1533

* if (optlen != TCPOLEN_WINDOW)

1534

* continue;

1535

* if (!(ti->ti_flags & TH_SYN))

1536

* continue;

1537

* tp->t_flags |= TF_RCVD_SCALE;

1538

* tp->requested_s_scale = min(cp[2], TCP_MAX_WINSHIFT);

1539

* break;

1540

1541

/* case TCPOPT_TIMESTAMP:

1542

* if (optlen != TCPOLEN_TIMESTAMP)

1543

* continue;

1544

* *ts_present = 1;

1545

* memcpy((char *) ts_val, (char *)cp + 2, sizeof(*ts_val));

1546

* NTOHL(*ts_val);

1547

* memcpy((char *) ts_ecr, (char *)cp + 6, sizeof(*ts_ecr));

1548

* NTOHL(*ts_ecr);

1549

1550

*/ /*

1551

* * A timestamp received in a SYN makes

1552

* * it ok to send timestamp requests and replies.

1553

* */

1554

/* if (ti->ti_flags & TH_SYN) {

1555

* tp->t_flags |= TF_RCVD_TSTMP;

1556

* tp->ts_recent = *ts_val;

1557

* tp->ts_recent_age = tcp_now;

1558

* }

1559

*/ break;

1560

}

1561

}

1562

}

1563

1564

1565

1566

* Pull out of band byte out of a segment so

1567

* it doesn't appear in the user's data queue.

1568

* It is still reflected in the segment length for

1569

* sequencing purposes.

1570

1571

1572

#ifdef notdef

1573

1574

void

1575

tcp_pulloutofband(so, ti, m)

1576

struct socket *so;

1577

struct tcpiphdr *ti;

1578

1579

{

1580

int cnt = ti->ti_urp - 1;

1581

1582

while (cnt >= 0) {

1583

if (m->m_len > cnt) {

1584

char *cp = mtod(m, caddr_t) + cnt;

1585

struct tcpcb *tp = sototcpcb(so);

1586

1587

tp->t_iobc = *cp;

1588

tp->t_oobflags |= TCPOOB_HAVEDATA;

1589

memcpy(sp, cp+1, (unsigned)(m->m_len - cnt - 1));

1590

m->m_len--;

1591

return;

1592

}

1593

cnt -= m->m_len;

1594

m = m->m_next; /* XXX WRONG! Fix it! */

1595

if (m == 0)

1596

break;

1597

}

1598

panic("tcp_pulloutofband");

1599

}

1600

1601

#endif /* notdef */

1602

1603

1604

* Collect new round-trip time estimate

1605

* and update averages and current timeout.

1606

1607

1608

void

1609

tcp_xmit_timer(tp, rtt)

1610

1611

int rtt;

1612

{

1613

1614

1615

DEBUG_CALL("tcp_xmit_timer");

1616

DEBUG_ARG("tp = %lx", (long)tp);

1617

DEBUG_ARG("rtt = %d", rtt);

1618

1619

tcpstat.tcps_rttupdated++;

1620

if (tp->t_srtt != 0) {

1621

1622

* srtt is stored as fixed point with 3 bits after the

1623

* binary point (i.e., scaled by 8). The following magic

1624

* is equivalent to the smoothing algorithm in rfc793 with

1625

* an alpha of .875 (srtt = rtt/8 + srtt*7/8 in fixed

1626

* point). Adjust rtt to origin 0.

1627

1628

delta = rtt - 1 - (tp->t_srtt >> TCP_RTT_SHIFT);

1629

if ((tp->t_srtt += delta) <= 0)

1630

tp->t_srtt = 1;

1631

1632

* We accumulate a smoothed rtt variance (actually, a

1633

* smoothed mean difference), then set the retransmit

1634

* timer to smoothed rtt + 4 times the smoothed variance.

1635

* rttvar is stored as fixed point with 2 bits after the

1636

* binary point (scaled by 4). The following is

1637

* equivalent to rfc793 smoothing with an alpha of .75

1638

* (rttvar = rttvar*3/4 + |delta| / 4). This replaces

1639

* rfc793's wired-in beta.

1640

1641

if (delta < 0)

1642

delta = -delta;

1643

delta -= (tp->t_rttvar >> TCP_RTTVAR_SHIFT);

1644

if ((tp->t_rttvar += delta) <= 0)

1645

tp->t_rttvar = 1;

1646

} else {

1647

1648

* No rtt measurement yet - use the unsmoothed rtt.

1649

* Set the variance to half the rtt (so our first

1650

* retransmit happens at 3*rtt).

1651

1652

tp->t_srtt = rtt << TCP_RTT_SHIFT;

1653

tp->t_rttvar = rtt << (TCP_RTTVAR_SHIFT - 1);

1654

}

1655

tp->t_rtt = 0;

1656

tp->t_rxtshift = 0;

1657

1658

1659

* the retransmit should happen at rtt + 4 * rttvar.

1660

* Because of the way we do the smoothing, srtt and rttvar

1661

* will each average +1/2 tick of bias. When we compute

1662

* the retransmit timer, we want 1/2 tick of rounding and

1663

* 1 extra tick because of +-1/2 tick uncertainty in the

1664

* firing of the timer. The bias will give us exactly the

1665

* 1.5 tick we need. But, because the bias is

1666

* statistical, we have to test that we don't drop below

1667

* the minimum feasible timer (which is 2 ticks).

1668

1669

TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp),

1670

(short)tp->t_rttmin, TCPTV_REXMTMAX); /* XXX */

1671

1672

1673

* We received an ack for a packet that wasn't retransmitted;

1674

* it is probably safe to discard any error indications we've

1675

* received recently. This isn't quite right, but close enough

1676

* for now (a route might have failed after we sent a segment,

1677

* and the return path might not be symmetrical).

1678

1679

tp->t_softerror = 0;

1680

}

1681

1682

1683

* Determine a reasonable value for maxseg size.

1684

* If the route is known, check route for mtu.

1685

* If none, use an mss that can be handled on the outgoing

1686

* interface without forcing IP to fragment; if bigger than

1687

* an mbuf cluster (MCLBYTES), round down to nearest multiple of MCLBYTES

1688

* to utilize large mbufs. If no route is found, route has no mtu,

1689

* or the destination isn't local, use a default, hopefully conservative

1690

* size (usually 512 or the default IP max size, but no more than the mtu

1691

* of the interface), as we can't discover anything about intervening

1692

* gateways or networks. We also initialize the congestion/slow start

1693

* window to be a single segment if the destination isn't local.

1694

* While looking at the routing entry, we also initialize other path-dependent

1695

* parameters from pre-set or cached values in the routing entry.

1696

1697

1698

int

1699

tcp_mss(tp, offer)

1700

1701

u_int offer;

1702

{

1703

struct socket *so = tp->t_socket;

1704

int mss;

1705

1706

DEBUG_CALL("tcp_mss");

1707

DEBUG_ARG("tp = %lx", (long)tp);

1708

DEBUG_ARG("offer = %d", offer);

1709

1710

mss = min(if_mtu, if_mru) - sizeof(struct tcpiphdr);

1711

if (offer)

1712

mss = min(mss, offer);

1713

mss = max(mss, 32);

1714

if (mss < tp->t_maxseg || offer != 0)

1715

tp->t_maxseg = mss;

1716

1717

tp->snd_cwnd = mss;

1718

1719

sbreserve(&so->so_snd, tcp_sndspace+((tcp_sndspace%mss)?(mss-(tcp_sndspace%mss)):0));

1720

sbreserve(&so->so_rcv, tcp_rcvspace+((tcp_rcvspace%mss)?(mss-(tcp_rcvspace%mss)):0));

1721

1722

DEBUG_MISC((dfd, " returning mss = %d\n", mss));

1723

1724

return mss;

1725

}

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