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* EAP common peer/server definitions
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* Copyright (c) 2004-2007, Jouni Malinen <j@w1.fi>
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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* Alternatively, this software may be distributed under the terms of BSD
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* See README and COPYING for more details.
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#include "eap_common.h"
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* eap_hdr_validate - Validate EAP header
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* @vendor: Expected EAP Vendor-Id (0 = IETF)
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* @eap_type: Expected EAP type number
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* @msg: EAP frame (starting with EAP header)
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* @plen: Pointer to variable to contain the returned payload length
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* Returns: Pointer to EAP payload (after type field), or %NULL on failure
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* This is a helper function for EAP method implementations. This is usually
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* called in the beginning of struct eap_method::process() function to verify
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* that the received EAP request packet has a valid header. This function is
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* able to process both legacy and expanded EAP headers and in most cases, the
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* caller can just use the returned payload pointer (into *plen) for processing
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* the payload regardless of whether the packet used the expanded EAP header or
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const u8 * eap_hdr_validate(int vendor, EapType eap_type,
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const struct wpabuf *msg, size_t *plen)
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const struct eap_hdr *hdr;
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hdr = wpabuf_head(msg);
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if (wpabuf_len(msg) < sizeof(*hdr)) {
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wpa_printf(MSG_INFO, "EAP: Too short EAP frame");
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len = be_to_host16(hdr->length);
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if (len < sizeof(*hdr) + 1 || len > wpabuf_len(msg)) {
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wpa_printf(MSG_INFO, "EAP: Invalid EAP length");
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pos = (const u8 *) (hdr + 1);
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if (*pos == EAP_TYPE_EXPANDED) {
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if (len < sizeof(*hdr) + 8) {
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wpa_printf(MSG_INFO, "EAP: Invalid expanded EAP "
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exp_vendor = WPA_GET_BE24(pos);
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exp_type = WPA_GET_BE32(pos);
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if (exp_vendor != vendor || exp_type != (u32) eap_type) {
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wpa_printf(MSG_INFO, "EAP: Invalid expanded frame "
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*plen = len - sizeof(*hdr) - 8;
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if (vendor != EAP_VENDOR_IETF || *pos != eap_type) {
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wpa_printf(MSG_INFO, "EAP: Invalid frame type");
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*plen = len - sizeof(*hdr) - 1;
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* eap_msg_alloc - Allocate a buffer for an EAP message
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* @vendor: Vendor-Id (0 = IETF)
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* @payload_len: Payload length in bytes (data after Type)
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* @code: Message Code (EAP_CODE_*)
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* @identifier: Identifier
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* Returns: Pointer to the allocated message buffer or %NULL on error
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* This function can be used to allocate a buffer for an EAP message and fill
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* in the EAP header. This function is automatically using expanded EAP header
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* if the selected Vendor-Id is not IETF. In other words, most EAP methods do
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* not need to separately select which header type to use when using this
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* function to allocate the message buffers. The returned buffer has room for
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* payload_len bytes and has the EAP header and Type field already filled in.
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struct wpabuf * eap_msg_alloc(int vendor, EapType type, size_t payload_len,
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u8 code, u8 identifier)
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len = sizeof(struct eap_hdr) + (vendor == EAP_VENDOR_IETF ? 1 : 8) +
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buf = wpabuf_alloc(len);
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hdr = wpabuf_put(buf, sizeof(*hdr));
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hdr->identifier = identifier;
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hdr->length = host_to_be16(len);
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if (vendor == EAP_VENDOR_IETF) {
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wpabuf_put_u8(buf, type);
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wpabuf_put_u8(buf, EAP_TYPE_EXPANDED);
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wpabuf_put_be24(buf, vendor);
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wpabuf_put_be32(buf, type);
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* eap_update_len - Update EAP header length
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* @msg: EAP message from eap_msg_alloc
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* This function updates the length field in the EAP header to match with the
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* current length for the buffer. This allows eap_msg_alloc() to be used to
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* allocate a larger buffer than the exact message length (e.g., if exact
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* message length is not yet known).
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void eap_update_len(struct wpabuf *msg)
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hdr = wpabuf_mhead(msg);
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if (wpabuf_len(msg) < sizeof(*hdr))
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hdr->length = host_to_be16(wpabuf_len(msg));
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* eap_get_id - Get EAP Identifier from wpabuf
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* @msg: Buffer starting with an EAP header
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* Returns: The Identifier field from the EAP header
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u8 eap_get_id(const struct wpabuf *msg)
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const struct eap_hdr *eap;
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if (wpabuf_len(msg) < sizeof(*eap))
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eap = wpabuf_head(msg);
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return eap->identifier;
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* eap_get_id - Get EAP Type from wpabuf
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* @msg: Buffer starting with an EAP header
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* Returns: The EAP Type after the EAP header
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EapType eap_get_type(const struct wpabuf *msg)
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if (wpabuf_len(msg) < sizeof(struct eap_hdr) + 1)
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return EAP_TYPE_NONE;
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return ((const u8 *) wpabuf_head(msg))[sizeof(struct eap_hdr)];