1 /***********************************************************************
5 * Implementation of user-space PPPoE redirector for Linux.
7 * Common functions used by PPPoE client and server
9 * Copyright (C) 2000 by Roaring Penguin Software Inc.
11 * This program may be distributed according to the terms of the GNU
12 * General Public License, version 2 or (at your option) any later version.
14 ***********************************************************************/
16 static char const RCSID[] =
17 "$Id: common.c,v 1.3 2008/06/09 08:34:23 paulus Exp $";
25 #include "pppd/pppd.h"
30 #include <syslog.h> /* for LOG_DEBUG */
36 /**********************************************************************
37 *%FUNCTION: parsePacket
39 * packet -- the PPPoE discovery packet to parse
40 * func -- function called for each tag in the packet
41 * extra -- an opaque data pointer supplied to parsing function
43 * 0 if everything went well; -1 if there was an error
45 * Parses a PPPoE discovery packet, calling "func" for each tag in the packet.
46 * "func" is passed the additional argument "extra".
47 ***********************************************************************/
49 parsePacket(PPPoEPacket *packet, ParseFunc *func, void *extra)
51 UINT16_t len = ntohs(packet->length);
52 unsigned char *curTag;
53 UINT16_t tagType, tagLen;
55 if (PPPOE_VER(packet->vertype) != 1) {
56 error("Invalid PPPoE version (%d)", PPPOE_VER(packet->vertype));
59 if (PPPOE_TYPE(packet->vertype) != 1) {
60 error("Invalid PPPoE type (%d)", PPPOE_TYPE(packet->vertype));
64 /* Do some sanity checks on packet */
65 if (len > ETH_JUMBO_LEN - PPPOE_OVERHEAD) { /* 6-byte overhead for PPPoE header */
66 error("Invalid PPPoE packet length (%u)", len);
70 /* Step through the tags */
71 curTag = packet->payload;
72 while (curTag - packet->payload + TAG_HDR_SIZE <= len) {
73 /* Alignment is not guaranteed, so do this by hand... */
74 tagType = (curTag[0] << 8) + curTag[1];
75 tagLen = (curTag[2] << 8) + curTag[3];
76 if (tagType == TAG_END_OF_LIST) {
79 if ((curTag - packet->payload) + tagLen + TAG_HDR_SIZE > len) {
80 error("Invalid PPPoE tag length (%u)", tagLen);
83 func(tagType, tagLen, curTag+TAG_HDR_SIZE, extra);
84 curTag = curTag + TAG_HDR_SIZE + tagLen;
89 /***********************************************************************
92 * conn -- PPPoE connection
93 * msg -- if non-NULL, extra error message to include in PADT packet.
98 ***********************************************************************/
100 sendPADT(PPPoEConnection *conn, char const *msg)
103 unsigned char *cursor = packet.payload;
107 /* Do nothing if no session established yet */
108 if (!conn->session) return;
110 /* Do nothing if no discovery socket */
111 if (conn->discoverySocket < 0) return;
113 memcpy(packet.ethHdr.h_dest, conn->peerEth, ETH_ALEN);
114 memcpy(packet.ethHdr.h_source, conn->myEth, ETH_ALEN);
116 packet.ethHdr.h_proto = htons(Eth_PPPOE_Discovery);
117 packet.vertype = PPPOE_VER_TYPE(1, 1);
118 packet.code = CODE_PADT;
119 packet.session = conn->session;
121 /* Reset Session to zero so there is no possibility of
122 recursive calls to this function by any signal handler */
125 /* If we're using Host-Uniq, copy it over */
126 if (conn->hostUniq.length) {
127 int len = ntohs(conn->hostUniq.length);
128 memcpy(cursor, &conn->hostUniq, len + TAG_HDR_SIZE);
129 cursor += len + TAG_HDR_SIZE;
130 plen += len + TAG_HDR_SIZE;
133 /* Copy error message */
136 size_t elen = strlen(msg);
137 err.type = htons(TAG_GENERIC_ERROR);
138 err.length = htons(elen);
139 strcpy(err.payload, msg);
140 memcpy(cursor, &err, elen + TAG_HDR_SIZE);
141 cursor += elen + TAG_HDR_SIZE;
142 plen += elen + TAG_HDR_SIZE;
145 /* Copy cookie and relay-ID if needed */
146 if (conn->cookie.type) {
147 CHECK_ROOM(cursor, packet.payload,
148 ntohs(conn->cookie.length) + TAG_HDR_SIZE);
149 memcpy(cursor, &conn->cookie, ntohs(conn->cookie.length) + TAG_HDR_SIZE);
150 cursor += ntohs(conn->cookie.length) + TAG_HDR_SIZE;
151 plen += ntohs(conn->cookie.length) + TAG_HDR_SIZE;
154 if (conn->relayId.type) {
155 CHECK_ROOM(cursor, packet.payload,
156 ntohs(conn->relayId.length) + TAG_HDR_SIZE);
157 memcpy(cursor, &conn->relayId, ntohs(conn->relayId.length) + TAG_HDR_SIZE);
158 cursor += ntohs(conn->relayId.length) + TAG_HDR_SIZE;
159 plen += ntohs(conn->relayId.length) + TAG_HDR_SIZE;
162 packet.length = htons(plen);
163 sendPacket(conn, conn->discoverySocket, &packet, (int) (plen + HDR_SIZE));
167 #define EH(x) (x)[0], (x)[1], (x)[2], (x)[3], (x)[4], (x)[5]
169 /* Print out a PPPOE packet for debugging */
170 void pppoe_printpkt(PPPoEPacket *packet,
171 void (*printer)(void *, char *, ...), void *arg)
173 int len = ntohs(packet->length);
174 int i, tag, tlen, text;
176 switch (ntohs(packet->ethHdr.h_proto)) {
177 case ETH_PPPOE_DISCOVERY:
178 printer(arg, "PPPOE Discovery V%dT%d ", PPPOE_VER(packet->vertype),
179 PPPOE_TYPE(packet->vertype));
180 switch (packet->code) {
182 printer(arg, "PADI");
185 printer(arg, "PADO");
188 printer(arg, "PADR");
191 printer(arg, "PADS");
194 printer(arg, "PADT");
197 printer(arg, "unknown code %x", packet->code);
199 printer(arg, " session 0x%x length %d\n", ntohs(packet->session), len);
201 case ETH_PPPOE_SESSION:
202 printer(arg, "PPPOE Session V%dT%d", PPPOE_VER(packet->vertype),
203 PPPOE_TYPE(packet->vertype));
204 printer(arg, " code 0x%x session 0x%x length %d\n", packet->code,
205 ntohs(packet->session), len);
208 printer(arg, "Unknown ethernet frame with proto = 0x%x\n",
209 ntohs(packet->ethHdr.h_proto));
212 printer(arg, " dst %02x:%02x:%02x:%02x:%02x:%02x ", EH(packet->ethHdr.h_dest));
213 printer(arg, " src %02x:%02x:%02x:%02x:%02x:%02x\n", EH(packet->ethHdr.h_source));
214 if (ntohs(packet->ethHdr.h_proto) != ETH_PPPOE_DISCOVERY)
217 for (i = 0; i + TAG_HDR_SIZE <= len; i += tlen) {
218 tag = (packet->payload[i] << 8) + packet->payload[i+1];
219 tlen = (packet->payload[i+2] << 8) + packet->payload[i+3];
220 if (i + tlen + TAG_HDR_SIZE > len)
226 case TAG_END_OF_LIST:
227 printer(arg, "end-of-list");
229 case TAG_SERVICE_NAME:
230 printer(arg, "service-name");
234 printer(arg, "AC-name");
238 printer(arg, "host-uniq");
241 printer(arg, "AC-cookie");
243 case TAG_VENDOR_SPECIFIC:
244 printer(arg, "vendor-specific");
246 case TAG_RELAY_SESSION_ID:
247 printer(arg, "relay-session-id");
249 case TAG_PPP_MAX_PAYLOAD:
250 printer(arg, "PPP-max-payload");
252 case TAG_SERVICE_NAME_ERROR:
253 printer(arg, "service-name-error");
256 case TAG_AC_SYSTEM_ERROR:
257 printer(arg, "AC-system-error");
260 case TAG_GENERIC_ERROR:
261 printer(arg, "generic-error");
265 printer(arg, "unknown tag 0x%x", tag);
269 printer(arg, " %.*v", tlen, &packet->payload[i]);
271 printer(arg, " %.*B", tlen, &packet->payload[i]);
273 printer(arg, " %.32B... (length %d)",
274 &packet->payload[i], tlen);
281 void pppoe_log_packet(const char *prefix, PPPoEPacket *packet)
283 init_pr_log(prefix, LOG_DEBUG);
284 pppoe_printpkt(packet, pr_log, NULL);