1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
|
/*
* Fred Griffoul <griffoul@ccrle.nec.de> sent me this file to use
* it when compiling pimd under Linux.
* There was no copyright message or author name, so I assume he was the
* author, and deserves the copyright/credit for it:
*
* COPYRIGHT/AUTHORSHIP by Fred Griffoul <griffoul@ccrle.nec.de>
* (until proven otherwise).
*/
#ifdef __linux__
#include <sys/param.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <netdb.h>
#include <stdlib.h>
#include <strings.h>
#include <paths.h>
#include "defs.h"
#include <linux/rtnetlink.h>
int routing_socket = -1;
static __u32 pid; /* pid_t, but /usr/include/linux/netlink.h says __u32 ... */
static __u32 seq;
static int getmsg(struct rtmsg *rtm, int msglen, struct rpfctl *rpf);
static int addattr32(struct nlmsghdr *n, size_t maxlen, int type, __u32 data)
{
int len = RTA_LENGTH(4);
struct rtattr *rta;
if (NLMSG_ALIGN(n->nlmsg_len) + len > maxlen)
return -1;
rta = (struct rtattr *) (((char *) n) + NLMSG_ALIGN(n->nlmsg_len));
rta->rta_type = type;
rta->rta_len = len;
memcpy(RTA_DATA(rta), &data, 4);
n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
return 0;
}
static int parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len)
{
while (RTA_OK(rta, len)) {
if (rta->rta_type <= max)
tb[rta->rta_type] = rta;
rta = RTA_NEXT(rta, len);
}
if (len)
logit(LOG_WARNING, 0, "NETLINK: Deficit in rtattr %d\n", len);
return 0;
}
/* open and initialize the routing socket */
int init_routesock(void)
{
socklen_t addr_len;
struct sockaddr_nl local;
routing_socket = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (routing_socket < 0) {
logit(LOG_ERR, errno, "netlink socket");
return -1;
}
memset(&local, 0, sizeof(local));
local.nl_family = AF_NETLINK;
local.nl_groups = 0;
if (bind(routing_socket, (struct sockaddr *) &local, sizeof(local)) < 0) {
logit(LOG_ERR, errno, "netlink bind");
return -1;
}
addr_len = sizeof(local);
if (getsockname(routing_socket, (struct sockaddr *) &local, &addr_len) < 0) {
logit(LOG_ERR, errno, "netlink getsockname");
return -1;
}
if (addr_len != sizeof(local)) {
logit(LOG_ERR, 0, "netlink wrong addr len");
return -1;
}
if (local.nl_family != AF_NETLINK) {
logit(LOG_ERR, 0, "netlink wrong addr family");
return -1;
}
pid = local.nl_pid;
seq = time(NULL);
return 0;
}
/* get the rpf neighbor info */
int k_req_incoming(u_int32 source, struct rpfctl *rpf)
{
int rlen;
register int l;
char buf[512];
struct nlmsghdr *n = (struct nlmsghdr *) buf;
struct rtmsg *r = NLMSG_DATA(n);
struct sockaddr_nl addr;
rpf->source.s_addr = source;
rpf->iif = ALL_VIFS;
rpf->rpfneighbor.s_addr = 0;
n->nlmsg_type = RTM_GETROUTE;
n->nlmsg_flags = NLM_F_REQUEST;
n->nlmsg_len = NLMSG_LENGTH(sizeof(*r));
n->nlmsg_pid = pid;
n->nlmsg_seq = ++seq;
memset(r, 0, sizeof(*r));
r->rtm_family = AF_INET;
r->rtm_dst_len = 32;
addattr32(n, sizeof(buf), RTA_DST, rpf->source.s_addr);
#ifdef CONFIG_RTNL_OLD_IFINFO
r->rtm_optlen = n->nlmsg_len - NLMSG_LENGTH(sizeof(*r));
#endif
addr.nl_family = AF_NETLINK;
addr.nl_groups = 0;
addr.nl_pid = 0;
/* tracef(TRF_NETLINK, "NETLINK: ask path to %s", inet_fmt(rpf->source.s_addr, s1, sizeof(s1))); */
logit(LOG_DEBUG, 0, "NETLINK: ask path to %s",
inet_fmt(rpf->source.s_addr, s1, sizeof(s1)));
while ((rlen = sendto(routing_socket, buf, n->nlmsg_len, 0, (struct sockaddr *) &addr, sizeof(addr))) < 0) {
if (errno == EINTR)
continue; /* Received signal, retry syscall. */
logit(LOG_WARNING, errno, "Error writing to routing socket");
return FALSE;
}
do {
socklen_t alen = sizeof(addr);
l = recvfrom(routing_socket, buf, sizeof(buf), 0, (struct sockaddr *) &addr, &alen);
if (l < 0) {
if (errno == EINTR)
continue; /* Received signal, retry syscall. */
logit(LOG_WARNING, errno, "Error writing to routing socket");
return FALSE;
}
} while (n->nlmsg_seq != seq || n->nlmsg_pid != pid);
if (n->nlmsg_type != RTM_NEWROUTE) {
if (n->nlmsg_type != NLMSG_ERROR) {
logit(LOG_WARNING, 0, "netlink: wrong answer type %d", n->nlmsg_type);
} else {
logit(LOG_WARNING, -(*(int*)NLMSG_DATA(n)), "netlink get_route");
}
return FALSE;
}
return getmsg(NLMSG_DATA(n), l - sizeof(*n), rpf);
}
static int getmsg(struct rtmsg *rtm, int msglen, struct rpfctl *rpf)
{
vifi_t vifi;
struct uvif *v;
struct rtattr *rta[RTA_MAX + 1];
if (rtm->rtm_type == RTN_LOCAL) {
/* tracef(TRF_NETLINK, "NETLINK: local address"); */
logit(LOG_DEBUG, 0, "NETLINK: local address");
if ((rpf->iif = local_address(rpf->source.s_addr)) != MAXVIFS) {
rpf->rpfneighbor.s_addr = rpf->source.s_addr;
return TRUE;
}
return FALSE;
}
rpf->rpfneighbor.s_addr = 0;
if (rtm->rtm_type != RTN_UNICAST) {
/* tracef(TRF_NETLINK, "NETLINK: route type is %d", rtm->rtm_type); */
logit(LOG_DEBUG, 0, "NETLINK: route type is %d", rtm->rtm_type);
return FALSE;
}
memset(rta, 0, sizeof(rta));
parse_rtattr(rta, RTA_MAX, RTM_RTA(rtm), msglen - sizeof(*rtm));
if (rta[RTA_OIF]) {
int ifindex = *(int *) RTA_DATA(rta[RTA_OIF]);
for (vifi = 0, v = uvifs; vifi < numvifs; ++vifi, ++v) {
if (v->uv_ifindex == ifindex)
break;
}
if (vifi >= numvifs) {
logit(LOG_WARNING, 0, "NETLINK: ifindex=%d, but no vif", ifindex);
return FALSE;
}
/* tracef(TRF_NETLINK, "NETLINK: vif %d, ifindex=%d", vifi, ifindex);*/
logit(LOG_DEBUG, 0, "NETLINK: vif %d, ifindex=%d", vifi, ifindex);
} else {
logit(LOG_WARNING, 0, "NETLINK: no interface");
return FALSE;
}
if (rta[RTA_GATEWAY]) {
__u32 gw = *(__u32 *) RTA_DATA(rta[RTA_GATEWAY]);
/* tracef(TRF_NETLINK, "NETLINK: gateway is %s", inet_fmt(gw, s1, sizeof(s1))); */
logit(LOG_DEBUG, 0, "NETLINK: gateway is %s", inet_fmt(gw, s1, sizeof(s1)));
rpf->rpfneighbor.s_addr = gw;
} else
rpf->rpfneighbor.s_addr = rpf->source.s_addr;
rpf->iif = vifi;
return TRUE;
}
#endif /* __linux__ */
/**
* Local Variables:
* version-control: t
* indent-tabs-mode: t
* c-file-style: "ellemtel"
* c-basic-offset: 4
* End:
*/
|