X-Git-Url: http://git.sameswireless.fr/l2tpns.git/blobdiff_plain/c94265dbc20a09b7efc872d2737b7c0acf82a91e..17b2ce31a692b0a82ab22e7d2aad1691eba0188c:/ppp.c?ds=inline diff --git a/ppp.c b/ppp.c index 809637c..25e6f8a 100644 --- a/ppp.c +++ b/ppp.c @@ -1,6 +1,6 @@ // L2TPNS PPP Stuff -char const *cvs_id_ppp = "$Id: ppp.c,v 1.24 2004/11/09 05:48:28 bodea Exp $"; +char const *cvs_id_ppp = "$Id: ppp.c,v 1.64 2005/06/24 08:34:53 bodea Exp $"; #include #include @@ -19,96 +19,106 @@ extern sessiont *session; extern radiust *radius; extern int tunfd; extern char hostname[]; -extern u32 eth_tx; +extern uint32_t eth_tx; extern time_t time_now; -extern struct configt *config; +extern configt *config; -void sendccp(tunnelidt t, sessionidt s); +static void initccp(tunnelidt t, sessionidt s); +static uint8_t *add_lcp_auth(uint8_t *b, int size, int authtype); // Process PAP messages -void processpap(tunnelidt t, sessionidt s, u8 *p, u16 l) +void processpap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) { - char user[129]; - char pass[129]; - u16 hl; + char user[MAXUSER]; + char pass[MAXPASS]; + uint16_t hl; - CSTAT(call_processpap); + CSTAT(processpap); LOG_HEX(5, "PAP", p, l); if (l < 4) { - LOG(1, 0, s, t, "Short PAP %u bytes\n", l); + LOG(1, s, t, "Short PAP %u bytes\n", l); STAT(tunnel_rx_errors); - return ; + sessionshutdown(s, "Short PAP packet.", 3, 0); + return; } - if ((hl = ntohs(*(u16 *) (p + 2))) > l) + if ((hl = ntohs(*(uint16_t *) (p + 2))) > l) { - LOG(1, 0, s, t, "Length mismatch PAP %u/%u\n", hl, l); + LOG(1, s, t, "Length mismatch PAP %u/%u\n", hl, l); STAT(tunnel_rx_errors); - return ; + sessionshutdown(s, "PAP length mismatch.", 3, 0); + return; } l = hl; if (*p != 1) { - LOG(1, 0, s, t, "Unexpected PAP code %d\n", *p); + LOG(1, s, t, "Unexpected PAP code %d\n", *p); STAT(tunnel_rx_errors); - return ; + sessionshutdown(s, "Unexpected PAP code.", 3, 0); + return; } { - u8 *b = p; + uint8_t *b = p; b += 4; + user[0] = pass[0] = 0; if (*b && *b < sizeof(user)) + { memcpy(user, b + 1, *b); - user[*b] = 0; - b += 1 + *b; - if (*b && *b < sizeof(pass)) - memcpy(pass, b + 1, *b); - pass[*b] = 0; - LOG(3, 0, s, t, "PAP login %s/%s\n", user, pass); + user[*b] = 0; + b += 1 + *b; + if (*b && *b < sizeof(pass)) + { + memcpy(pass, b + 1, *b); + pass[*b] = 0; + } + } + LOG(3, s, t, "PAP login %s/%s\n", user, pass); } - if (session[s].ip || !session[s].radius) + if (session[s].ip || !sess_local[s].radius) { // respond now, either no RADIUS available or already authenticated - u8 b[MAXCONTROL]; - u8 id = p[1]; - u8 *p = makeppp(b, sizeof(b), 0, 0, t, s, PPPPAP); - if (!p) { // Failed to make ppp header! - LOG(1,0,0,0, "Failed to make PPP header in process pap!\n"); - return; - } + uint8_t b[MAXCONTROL]; + uint8_t id = p[1]; + uint8_t *p = makeppp(b, sizeof(b), 0, 0, t, s, PPPPAP); + if (!p) return; + if (session[s].ip) - *p = 2; // ACK + *p = 2; // ACK else - *p = 3; // cant authorise + *p = 3; // cant authorise p[1] = id; - *(u16 *) (p + 2) = htons(5); // length - p[4] = 0; // no message + *(uint16_t *) (p + 2) = htons(5); // length + p[4] = 0; // no message if (session[s].ip) { - LOG(3, session[s].ip, s, t, "Already an IP allocated: %s (%d)\n", inet_toa(htonl(session[s].ip)), session[s].ip_pool_index); + LOG(3, s, t, "Already an IP allocated: %s (%d)\n", + fmtaddr(htonl(session[s].ip), 0), session[s].ip_pool_index); + session[s].flags &= ~SF_IPCP_ACKED; } else { - LOG(1, 0, s, t, "No radius session available to authenticate session...\n"); + LOG(1, s, t, "No radius session available to authenticate session...\n"); } - LOG(3, 0, s, t, "Fallback response to PAP (%s)\n", (session[s].ip) ? "ACK" : "NAK"); + LOG(3, s, t, "Fallback response to PAP (%s)\n", (session[s].ip) ? "ACK" : "NAK"); tunnelsend(b, 5 + (p - b), t); // send it + sessionshutdown(s, "PAP authentication failed.", 3, 0); } else { // set up RADIUS request - u16 r = session[s].radius; + uint16_t r = sess_local[s].radius; // Run PRE_AUTH plugins struct param_pre_auth packet = { &tunnel[t], &session[s], strdup(user), strdup(pass), PPPPAP, 1 }; run_plugins(PLUGIN_PRE_AUTH, &packet); if (!packet.continue_auth) { - LOG(3, 0, s, t, "A plugin rejected PRE_AUTH\n"); + LOG(3, s, t, "A plugin rejected PRE_AUTH\n"); if (packet.username) free(packet.username); if (packet.password) free(packet.password); return; @@ -121,73 +131,76 @@ void processpap(tunnelidt t, sessionidt s, u8 *p, u16 l) free(packet.password); radius[r].id = p[1]; - LOG(3, 0, s, t, "Sending login for %s/%s to radius\n", user, pass); + LOG(3, s, t, "Sending login for %s/%s to radius\n", user, pass); radiussend(r, RADIUSAUTH); } } // Process CHAP messages -void processchap(tunnelidt t, sessionidt s, u8 *p, u16 l) +void processchap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) { - u16 r; - u16 hl; + uint16_t r; + uint16_t hl; - CSTAT(call_processchap); + CSTAT(processchap); LOG_HEX(5, "CHAP", p, l); - r = session[s].radius; + r = sess_local[s].radius; if (!r) { - LOG(1, 0, s, t, "Unexpected CHAP message\n"); - -// FIXME: Need to drop the session here. - + LOG(1, s, t, "Unexpected CHAP message\n"); STAT(tunnel_rx_errors); return; } if (l < 4) { - LOG(1, 0, s, t, "Short CHAP %u bytes\n", l); + LOG(1, s, t, "Short CHAP %u bytes\n", l); STAT(tunnel_rx_errors); - return ; + sessionshutdown(s, "Short CHAP packet.", 3, 0); + return; } - if ((hl = ntohs(*(u16 *) (p + 2))) > l) + if ((hl = ntohs(*(uint16_t *) (p + 2))) > l) { - LOG(1, 0, s, t, "Length mismatch CHAP %u/%u\n", hl, l); + LOG(1, s, t, "Length mismatch CHAP %u/%u\n", hl, l); STAT(tunnel_rx_errors); - return ; + sessionshutdown(s, "CHAP length mismatch.", 3, 0); + return; } l = hl; if (*p != 2) { - LOG(1, 0, s, t, "Unexpected CHAP response code %d\n", *p); + LOG(1, s, t, "Unexpected CHAP response code %d\n", *p); STAT(tunnel_rx_errors); + sessionshutdown(s, "CHAP length mismatch.", 3, 0); return; } if (p[1] != radius[r].id) { - LOG(1, 0, s, t, "Wrong CHAP response ID %d (should be %d) (%d)\n", p[1], radius[r].id, r); + LOG(1, s, t, "Wrong CHAP response ID %d (should be %d) (%d)\n", p[1], radius[r].id, r); STAT(tunnel_rx_errors); - return ; + sessionshutdown(s, "Unexpected CHAP response ID.", 3, 0); + return; } if (l < 5 || p[4] != 16) { - LOG(1, 0, s, t, "Bad CHAP response length %d\n", l < 5 ? -1 : p[4]); + LOG(1, s, t, "Bad CHAP response length %d\n", l < 5 ? -1 : p[4]); STAT(tunnel_rx_errors); - return ; + sessionshutdown(s, "Bad CHAP response length.", 3, 0); + return; } l -= 5; p += 5; if (l < 16 || l - 16 >= sizeof(session[s].user)) { - LOG(1, 0, s, t, "CHAP user too long %d\n", l - 16); + LOG(1, s, t, "CHAP user too long %d\n", l - 16); STAT(tunnel_rx_errors); - return ; + sessionshutdown(s, "CHAP username too long.", 3, 0); + return; } // Run PRE_AUTH plugins @@ -206,7 +219,7 @@ void processchap(tunnelidt t, sessionidt s, u8 *p, u16 l) run_plugins(PLUGIN_PRE_AUTH, &packet); if (!packet.continue_auth) { - LOG(3, 0, s, t, "A plugin rejected PRE_AUTH\n"); + LOG(3, s, t, "A plugin rejected PRE_AUTH\n"); if (packet.username) free(packet.username); if (packet.password) free(packet.password); return; @@ -220,34 +233,18 @@ void processchap(tunnelidt t, sessionidt s, u8 *p, u16 l) } radius[r].chap = 1; - LOG(3, 0, s, t, "CHAP login %s\n", session[s].user); + LOG(3, s, t, "CHAP login %s\n", session[s].user); radiussend(r, RADIUSAUTH); } -char *ppp_lcp_types[] = { - NULL, - "ConfigReq", - "ConfigAck", - "ConfigNak", - "ConfigRej", - "TerminateReq", - "TerminateAck", - "CodeRej", - "ProtocolRej", - "EchoReq", - "EchoReply", - "DiscardRequest", - "IdentRequest", -}; - -void dumplcp(u8 *p, int l) +static void dumplcp(uint8_t *p, int l) { int x = l - 4; - u8 *o = (p + 4); + uint8_t *o = (p + 4); LOG_HEX(5, "PPP LCP Packet", p, l); - LOG(4, 0, 0, 0, "PPP LCP Packet type %d (%s len %d)\n", *p, ppp_lcp_types[(int)*p], ntohs( ((u16 *) p)[1]) ); - LOG(4, 0, 0, 0, "Length: %d\n", l); + LOG(4, 0, 0, "PPP LCP Packet type %d (%s len %d)\n", *p, ppp_lcp_type((int)*p), ntohs( ((uint16_t *) p)[1]) ); + LOG(4, 0, 0, "Length: %d\n", l); if (*p != ConfigReq && *p != ConfigRej && *p != ConfigAck) return; @@ -257,12 +254,12 @@ void dumplcp(u8 *p, int l) int length = o[1]; if (length < 2) { - LOG(4, 0, 0, 0, " Option length is %d...\n", length); + LOG(4, 0, 0, " Option length is %d...\n", length); break; } if (type == 0) { - LOG(4, 0, 0, 0, " Option type is 0...\n"); + LOG(4, 0, 0, " Option type is 0...\n"); x -= length; o += length; continue; @@ -271,51 +268,57 @@ void dumplcp(u8 *p, int l) { case 1: // Maximum-Receive-Unit if (length == 4) - LOG(4, 0, 0, 0, " %s %d\n", lcp_types[type], ntohs(*(u16 *)(o + 2))); + LOG(4, 0, 0, " %s %d\n", lcp_type(type), ntohs(*(uint16_t *)(o + 2))); else - LOG(4, 0, 0, 0, " %s odd length %d\n", lcp_types[type], length); + LOG(4, 0, 0, " %s odd length %d\n", lcp_type(type), length); break; case 2: // Async-Control-Character-Map if (length == 6) { - u32 asyncmap = ntohl(*(u32 *)(o + 2)); - LOG(4, 0, 0, 0, " %s %x\n", lcp_types[type], asyncmap); + uint32_t asyncmap = ntohl(*(uint32_t *)(o + 2)); + LOG(4, 0, 0, " %s %x\n", lcp_type(type), asyncmap); } else - LOG(4, 0, 0, 0, " %s odd length %d\n", lcp_types[type], length); + LOG(4, 0, 0, " %s odd length %d\n", lcp_type(type), length); break; case 3: // Authentication-Protocol if (length == 4) { - int proto = ntohs(*(u16 *)(o + 2)); - LOG(4, 0, 0, 0, " %s 0x%x (%s)\n", lcp_types[type], proto, - proto == PPPCHAP ? "CHAP" : - proto == PPPPAP ? "PAP" : "UNKNOWN"); + int proto = ntohs(*(uint16_t *)(o + 2)); + LOG(4, 0, 0, " %s 0x%x (%s)\n", lcp_type(type), proto, + proto == PPPPAP ? "PAP" : "UNSUPPORTED"); + } + else if (length == 5) + { + int proto = ntohs(*(uint16_t *)(o + 2)); + int algo = *(uint8_t *)(o + 4); + LOG(4, 0, 0, " %s 0x%x 0x%x (%s)\n", lcp_type(type), proto, algo, + (proto == PPPCHAP && algo == 5) ? "CHAP MD5" : "UNSUPPORTED"); } else - LOG(4, 0, 0, 0, " %s odd length %d\n", lcp_types[type], length); + LOG(4, 0, 0, " %s odd length %d\n", lcp_type(type), length); break; case 4: // Quality-Protocol { - u32 qp = ntohl(*(u32 *)(o + 2)); - LOG(4, 0, 0, 0, " %s %x\n", lcp_types[type], qp); + uint32_t qp = ntohl(*(uint32_t *)(o + 2)); + LOG(4, 0, 0, " %s %x\n", lcp_type(type), qp); } break; case 5: // Magic-Number if (length == 6) { - u32 magicno = ntohl(*(u32 *)(o + 2)); - LOG(4, 0, 0, 0, " %s %x\n", lcp_types[type], magicno); + uint32_t magicno = ntohl(*(uint32_t *)(o + 2)); + LOG(4, 0, 0, " %s %x\n", lcp_type(type), magicno); } else - LOG(4, 0, 0, 0, " %s odd length %d\n", lcp_types[type], length); + LOG(4, 0, 0, " %s odd length %d\n", lcp_type(type), length); break; case 7: // Protocol-Field-Compression case 8: // Address-And-Control-Field-Compression - LOG(4, 0, 0, 0, " %s\n", lcp_types[type]); + LOG(4, 0, 0, " %s\n", lcp_type(type)); break; default: - LOG(2, 0, 0, 0, " Unknown PPP LCP Option type %d\n", type); + LOG(2, 0, 0, " Unknown PPP LCP Option type %d\n", type); break; } x -= length; @@ -324,26 +327,26 @@ void dumplcp(u8 *p, int l) } // Process LCP messages -void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l) +void processlcp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) { - u8 b[MAXCONTROL]; - u8 *q = NULL; - u32 magicno = 0; - u16 hl; + uint8_t b[MAXCONTROL]; + uint8_t *q = NULL; + uint32_t magicno = 0; + uint16_t hl; - CSTAT(call_processlcp); + CSTAT(processlcp); LOG_HEX(5, "LCP", p, l); if (l < 4) { - LOG(1, session[s].ip, s, t, "Short LCP %d bytes\n", l); + LOG(1, s, t, "Short LCP %d bytes\n", l); STAT(tunnel_rx_errors); return ; } - if ((hl = ntohs(*(u16 *) (p + 2))) > l) + if ((hl = ntohs(*(uint16_t *) (p + 2))) > l) { - LOG(1, 0, s, t, "Length mismatch LCP %u/%u\n", hl, l); + LOG(1, s, t, "Length mismatch LCP %u/%u\n", hl, l); STAT(tunnel_rx_errors); return ; } @@ -351,47 +354,78 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l) if (*p == ConfigAck) { - LOG(3, session[s].ip, s, t, "LCP: Discarding ConfigAck\n"); + int x = l - 4; + uint8_t *o = (p + 4); + + LOG(3, s, t, "LCP: ConfigAck (%d bytes)...\n", l); + if (config->debug > 3) dumplcp(p, l); + + while (x > 2) + { + int type = o[0]; + int length = o[1]; + + if (length == 0 || type == 0 || x < length) break; + switch (type) + { + case 3: // Authentication-Protocol + { + int proto = ntohs(*(uint16_t *)(o + 2)); + if (proto == PPPCHAP && *(o + 4) == 5) + sendchap(t, s); + } + + break; + } + x -= length; + o += length; + } + session[s].flags |= SF_LCP_ACKED; } else if (*p == ConfigReq) { int x = l - 4; - u8 *o = (p + 4); - u8 response = 0; + uint8_t *o = (p + 4); + uint8_t *response = 0; - LOG(3, session[s].ip, s, t, "LCP: ConfigReq (%d bytes)...\n", l); + LOG(3, s, t, "LCP: ConfigReq (%d bytes)...\n", l); if (config->debug > 3) dumplcp(p, l); while (x > 2) { int type = o[0]; int length = o[1]; + if (length == 0 || type == 0 || x < length) break; switch (type) { case 1: // Maximum-Receive-Unit - session[s].mru = ntohs(*(u16 *)(o + 2)); + session[s].mru = ntohs(*(uint16_t *)(o + 2)); break; case 2: // Async-Control-Character-Map - if (!ntohl(*(u32 *)(o + 2))) // all bits zero is OK + if (!ntohl(*(uint32_t *)(o + 2))) // all bits zero is OK break; - if (response && response != ConfigNak) // rej already queued + if (response && *response != ConfigNak) // rej already queued break; - LOG(2, session[s].ip, s, t, " Remote requesting asyncmap. Rejecting.\n"); + LOG(2, s, t, " Remote requesting asyncmap. Rejecting.\n"); if (!response) { - q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP); - if (!q) - { - LOG(2, session[s].ip, s, t, " Failed to send packet.\n"); - break; - } - response = *q++ = ConfigNak; + q = response = makeppp(b, sizeof(b), p, 2, t, s, PPPLCP); + if (!q) break; + *q = ConfigNak; + q += 4; + } + + if ((q - b + 11) > sizeof(b)) + { + LOG(2, s, t, "LCP overflow for asyncmap ConfigNak.\n"); + break; } + *q++ = type; *q++ = 6; memset(q, 0, 4); // asyncmap 0 @@ -400,39 +434,68 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l) case 3: // Authentication-Protocol { - int proto = ntohs(*(u16 *)(o + 2)); + int proto = ntohs(*(uint16_t *)(o + 2)); char proto_name[] = "0x0000"; + uint8_t *a; + if (proto == PPPPAP) - break; + { + if (config->radius_authtypes & AUTHPAP) + break; - if (response && response != ConfigNak) // rej already queued - break; + strcpy(proto_name, "PAP"); + } + else if (proto == PPPCHAP) + { + if (config->radius_authtypes & AUTHCHAP + && *(o + 4) == 5) // MD5 + break; - if (proto == PPPCHAP) strcpy(proto_name, "CHAP"); + } else sprintf(proto_name, "%#4.4x", proto); - LOG(2, session[s].ip, s, t, " Remote requesting %s authentication. Rejecting.\n", proto_name); + if (response && *response != ConfigNak) // rej already queued + break; + + LOG(2, s, t, " Remote requesting %s authentication. Rejecting.\n", proto_name); if (!response) { - q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP); - if (!q) + q = response = makeppp(b, sizeof(b), p, 2, t, s, PPPLCP); + if (!q) break; + *q = ConfigNak; + q += 4; + } + + a = add_lcp_auth(q, sizeof(b) - (q - b), config->radius_authprefer); + if (!a) + { + LOG(2, s, t, "LCP overflow for %s ConfigNak.\n", proto_name); + break; + } + + q = a; + + if (config->radius_authtypes != config->radius_authprefer) + { + a = add_lcp_auth(q, sizeof(b) - (q - b), config->radius_authtypes & ~config->radius_authprefer); + if (!a) { - LOG(2, session[s].ip, s, t, " Failed to send packet.\n"); + LOG(2, s, t, "LCP overflow for %s ConfigNak.\n", proto_name); break; } - response = *q++ = ConfigNak; + + q = a; } - memcpy(q, o, length); - *(u16 *)(q += 2) = htons(PPPPAP); // NAK -> Use PAP instead - q += length; + + break; } break; case 5: // Magic-Number - magicno = ntohl(*(u32 *)(o + 2)); + magicno = ntohl(*(uint32_t *)(o + 2)); break; case 4: // Quality-Protocol @@ -441,16 +504,19 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l) break; default: // Reject any unknown options - LOG(2, session[s].ip, s, t, " Rejecting PPP LCP Option type %d\n", type); - if (!response || response != ConfigRej) // drop nak in favour of rej + LOG(2, s, t, " Rejecting PPP LCP Option type %d\n", type); + if (!response || *response != ConfigRej) // drop nak in favour of rej { - q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP); - if (!q) - { - LOG(2, session[s].ip, s, t, " Failed to send packet.\n"); - break; - } - response = *q++ = ConfigRej; + q = response = makeppp(b, sizeof(b), p, 2, t, s, PPPLCP); + if (!q) break; + *q = ConfigRej; + q += 4; + } + + if ((q - b + length) > sizeof(b)) + { + LOG(2, s, t, "LCP overflow for ConfigRej (type=%d).\n", type); + break; } memcpy(q, o, length); @@ -460,58 +526,127 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l) o += length; } - if (!response) + if (response) { - // Send back a ConfigAck - q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP); - if (!q) - { - LOG(3, session[s].ip, s, t, " failed to create packet.\n"); - return; - } - response = *q = ConfigAck; + l = q - response; // LCP packet length + *((uint16_t *) (response + 2)) = htons(l); // update header + } + else + { + // Send packet back as ConfigAck + response = makeppp(b, sizeof(b), p, l, t, s, PPPLCP); + if (!response) return; + *response = ConfigAck; } - LOG(3, session[s].ip, s, t, "Sending %s\n", ppp_lcp_types[response]); - tunnelsend(b, l + (q - b), t); + LOG(3, s, t, "Sending %s\n", ppp_lcp_type(*response)); + tunnelsend(b, l + response - b, t); if (!(session[s].flags & SF_LCP_ACKED)) - initlcp(t, s); + sendlcp(t, s, config->radius_authprefer); } else if (*p == ConfigNak) { - LOG(1, session[s].ip, s, t, "Remote end sent a ConfigNak. Ignoring\n"); + int x = l - 4; + uint8_t *o = (p + 4); + int authtype = -1; + + LOG(3, s, t, "LCP: ConfigNak (%d bytes)...\n", l); if (config->debug > 3) dumplcp(p, l); - return ; + + while (x > 2) + { + int type = o[0]; + int length = o[1]; + + if (length == 0 || type == 0 || x < length) break; + switch (type) + { + case 1: // Maximum-Receive-Unit + session[s].mru = ntohs(*(uint16_t *)(o + 2)); + LOG(3, s, t, " Remote requested MRU of %u\n", session[s].mru); + break; + + case 3: // Authentication-Protocol + if (authtype > 0) + break; + + { + int proto = ntohs(*(uint16_t *)(o + 2)); + if (proto == PPPPAP) + { + authtype = config->radius_authtypes & AUTHPAP; + LOG(3, s, t, " Remote requested PAP authentication...%sing\n", + authtype ? "accept" : "reject"); + } + else if (proto == PPPCHAP && *(o + 4) == 5) + { + authtype = config->radius_authtypes & AUTHCHAP; + LOG(3, s, t, " Remote requested CHAP authentication...%sing\n", + authtype ? "accept" : "reject"); + } + else + { + LOG(3, s, t, " Rejecting unsupported authentication %#4x\n", + proto); + } + } + + break; + + default: + LOG(2, s, t, " Remote NAKed LCP type %u?\n", type); + break; + } + x -= length; + o += length; + } + + if (!authtype) + { + sessionshutdown(s, "Unsupported authentication.", 3, 0); + return; + } + + if (authtype == -1) + authtype = config->radius_authprefer; + + sendlcp(t, s, authtype); } else if (*p == TerminateReq) { + LOG(3, s, t, "LCP: Received TerminateReq. Sending TerminateAck\n"); *p = TerminateAck; // close q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP); - if (!q) - { - LOG(3, session[s].ip, s, t, "Failed to create PPP packet in processlcp.\n"); - return; - } - LOG(3, session[s].ip, s, t, "LCP: Received TerminateReq. Sending TerminateAck\n"); - sessionshutdown(s, "Remote end closed connection."); + if (!q) return; tunnelsend(b, l + (q - b), t); // send it + sessionshutdown(s, "Remote end closed connection.", 3, 0); } else if (*p == TerminateAck) { - sessionshutdown(s, "Connection closed."); + sessionshutdown(s, "Connection closed.", 3, 0); + } + else if (*p == ProtocolRej) + { + if (*(uint16_t *) (p+4) == htons(PPPIPV6CP)) + { + LOG(3, s, t, "IPv6 rejected\n"); + session[s].flags |= SF_IPV6_NACKED; + } + else + { + LOG(1, s, t, "Unexpected LCP protocol reject 0x%X\n", + ntohs(*(uint16_t *) (p+4))); + STAT(tunnel_rx_errors); + } } else if (*p == EchoReq) { + LOG(5, s, t, "LCP: Received EchoReq. Sending EchoReply\n"); *p = EchoReply; // reply - *(u32 *) (p + 4) = htonl(session[s].magic); // our magic number + *(uint32_t *) (p + 4) = htonl(session[s].magic); // our magic number q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP); - if (!q) - { - LOG(3, session[s].ip, s, t, " failed to send EchoReply.\n"); - return; - } - LOG(5, session[s].ip, s, t, "LCP: Received EchoReq. Sending EchoReply\n"); + if (!q) return; tunnelsend(b, l + (q - b), t); // send it } else if (*p == EchoReply) @@ -523,44 +658,59 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l) *p = CodeRej; if (l > MAXCONTROL) { - LOG(1, 0, s, t, "Truncated Ident Packet (length=%d) to 1400 bytes\n", l); + LOG(1, s, t, "Truncated Ident Packet (length=%d) to 1400 bytes\n", l); l = 1400; } q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP); - if (!q) - { - LOG(3, session[s].ip, s, t, "Failed to create IdentRej.\n"); - return; - } + if (!q) return; LOG_HEX(5, "LCPIdentRej", q, l + 4); tunnelsend(b, 12 + 4 + l, t); } else { - LOG(1, session[s].ip, s, t, "Unexpected LCP code %d\n", *p); + LOG(1, s, t, "Unexpected LCP code %d\n", *p); STAT(tunnel_rx_errors); - return ; } } +// find a PPP option, returns point to option, or 0 if not found +static uint8_t *findppp(uint8_t *b, uint8_t mtype) +{ + uint16_t l = ntohs(*(uint16_t *) (b + 2)); + if (l < 4) + return 0; + b += 4; + l -= 4; + while (l) + { + if (l < b[1] || !b[1]) + return 0; // faulty + if (*b == mtype) + return b; + l -= b[1]; + b += b[1]; + } + return 0; +} + // Process IPCP messages -void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l) +void processipcp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) { - u16 hl; + uint16_t hl; - CSTAT(call_processipcp); + CSTAT(processipcp); LOG_HEX(5, "IPCP", p, l); if (l < 5) { - LOG(1, 0, s, t, "Short IPCP %d bytes\n", l); + LOG(1, s, t, "Short IPCP %d bytes\n", l); STAT(tunnel_rx_errors); return ; } - if ((hl = ntohs(*(u16 *) (p + 2))) > l) + if ((hl = ntohs(*(uint16_t *) (p + 2))) > l) { - LOG(1, 0, s, t, "Length mismatch IPCP %u/%u\n", hl, l); + LOG(1, s, t, "Length mismatch IPCP %u/%u\n", hl, l); STAT(tunnel_rx_errors); return ; } @@ -568,38 +718,51 @@ void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l) if (*p == ConfigAck) { + uint16_t r = sess_local[s].radius; + + // ignore duplicate ACKs + if (session[s].flags & SF_IPCP_ACKED) + return; + // happy with our IPCP - u16 r = session[s].radius; - if ((!r || radius[r].state == RADIUSIPCP) && !session[s].walled_garden) + session[s].flags |= SF_IPCP_ACKED; + + LOG(3, s, t, "IPCP Acked, session is now active\n"); + + // clear LCP_ACKED/CCP_ACKED flag for possible fast renegotiation for routers + session[s].flags &= ~(SF_LCP_ACKED|SF_CCP_ACKED); + + if (r && session[s].walled_garden) { - if (!r) - r = radiusnew(s); - if (r) - radiussend(r, RADIUSSTART); // send radius start, having got IPCP at last + radiusclear(r, s); + return; } - session[s].flags |= SF_IPCP_ACKED; - LOG(3, session[s].ip, s, t, "IPCP Acked, session is now active\n"); + if (!r) + r = radiusnew(s); + + if (r) + radiussend(r, RADIUSSTART); // send radius start, having got IPCP at last + return; } if (*p != ConfigReq) { - LOG(1, 0, s, t, "Unexpected IPCP code %d\n", *p); + LOG(1, s, t, "Unexpected IPCP code %d\n", *p); STAT(tunnel_rx_errors); return ; } - LOG(4, session[s].ip, s, t, "IPCP ConfigReq received\n"); + LOG(4, s, t, "IPCP ConfigReq received\n"); if (!session[s].ip) { - LOG(3, 0, s, t, "Waiting on radius reply\n"); + LOG(3, s, t, "Waiting on radius reply\n"); return; // have to wait on RADIUS reply } // form a config reply quoting the IP in the session { - u8 b[MAXCONTROL]; - u8 *i, - *q; + uint8_t b[MAXCONTROL]; + uint8_t *i, *q; q = p + 4; i = p + l; @@ -612,68 +775,188 @@ void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l) if (q < i) { // reject - u16 n = 4; + uint16_t n = 4; i = p + l; if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP))) - { - LOG(2, 0, s, t, "Failed to send IPCP ConfigRej\n"); return; - } + *q = ConfigRej; p += 4; while (p < i && p[1]) { if (*p != 0x81 && *p != 0x83 && *p != 3) { - LOG(2, 0, s, t, "IPCP reject %d\n", *p); + LOG(2, s, t, "IPCP reject %d\n", *p); memcpy(q + n, p, p[1]); n += p[1]; } p += p[1]; } - *(u16 *) (q + 2) = htons(n); - LOG(4, session[s].ip, s, t, "Sending ConfigRej\n"); + *(uint16_t *) (q + 2) = htons(n); + LOG(4, s, t, "Sending ConfigRej\n"); tunnelsend(b, n + (q - b), t); // send it } else { - LOG(4, session[s].ip, s, t, "Sending ConfigAck\n"); + LOG(4, s, t, "Sending ConfigAck\n"); *p = ConfigAck; if ((i = findppp(p, 0x81))) // Primary DNS address { - if (*(u32 *) (i + 2) != htonl(session[s].dns1)) + if (*(uint32_t *) (i + 2) != htonl(session[s].dns1)) { - *(u32 *) (i + 2) = htonl(session[s].dns1); + *(uint32_t *) (i + 2) = htonl(session[s].dns1); *p = ConfigNak; - LOG(5, session[s].ip, s, t, " DNS1 = %s\n", inet_toa(session[s].dns1)); + LOG(5, s, t, " DNS1 = %s\n", + fmtaddr(htonl(session[s].dns1), 0)); } } if ((i = findppp(p, 0x83))) // Secondary DNS address (TBA, is it) { - if (*(u32 *) (i + 2) != htonl(session[s].dns2)) + if (*(uint32_t *) (i + 2) != htonl(session[s].dns2)) { - *(u32 *) (i + 2) = htonl(session[s].dns2); + *(uint32_t *) (i + 2) = htonl(session[s].dns2); *p = ConfigNak; - LOG(5, session[s].ip, s, t, " DNS2 = %s\n", inet_toa(session[s].dns2)); + LOG(5, s, t, " DNS2 = %s\n", + fmtaddr(htonl(session[s].dns2), 0)); } } i = findppp(p, 3); // IP address if (!i || i[1] != 6) { - LOG(1, 0, s, t, "No IP in IPCP request\n"); + LOG(1, s, t, "No IP in IPCP request\n"); STAT(tunnel_rx_errors); return ; } - if (*(u32 *) (i + 2) != htonl(session[s].ip)) + if (*(uint32_t *) (i + 2) != htonl(session[s].ip)) { - *(u32 *) (i + 2) = htonl(session[s].ip); + *(uint32_t *) (i + 2) = htonl(session[s].ip); *p = ConfigNak; - LOG(4, session[s].ip, s, t, " No, a ConfigNak, client is requesting IP - sending %s\n", - inet_toa(htonl(session[s].ip))); + LOG(4, s, t, " No, a ConfigNak, client is requesting IP - sending %s\n", + fmtaddr(htonl(session[s].ip), 0)); } if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP))) + return; + + tunnelsend(b, l + (q - b), t); // send it + } + } +} + +// Process IPV6CP messages +void processipv6cp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) +{ + + CSTAT(processipv6cp); + + LOG_HEX(5, "IPV6CP", p, l); + if (l < 4) + { + LOG(1, s, t, "Short IPV6CP %d bytes\n", l); + STAT(tunnel_rx_errors); + return ; + } + if (*p == ConfigAck) + { + // happy with our IPV6CP + session[s].flags |= SF_IPV6CP_ACKED; + + LOG(3, s, t, "IPV6CP Acked, IPv6 is now active\n"); + // Add a routed block if configured. + if (session[s].ipv6prefixlen) + { + route6set(s, session[s].ipv6route, session[s].ipv6prefixlen, 1); + session[s].flags |= SF_IPV6_ROUTED; + } + + // Send an initial RA (TODO: Should we send these regularly?) + send_ipv6_ra(t, s, NULL); + return; + } + if (*p != ConfigReq) + { + LOG(1, s, t, "Unexpected IPV6CP code %d\n", *p); + STAT(tunnel_rx_errors); + return; + } + + LOG(4, s, t, "IPV6CP ConfigReq received\n"); + if (ntohs(*(uint16_t *) (p + 2)) > l) + { + LOG(1, s, t, "Length mismatch IPV6CP %d/%d\n", ntohs(*(uint16_t *) (p + 2)), l); + STAT(tunnel_rx_errors); + return ; + } + if (!session[s].ip) + { + LOG(3, s, t, "Waiting on radius reply\n"); + return; // have to wait on RADIUS reply + } + // form a config reply quoting the IP in the session + { + uint8_t b[MAXCONTROL]; + uint8_t *i, + *q; + + l = ntohs(*(uint16_t *) (p + 2)); // We must use length from IPV6CP len field + q = p + 4; + i = p + l; + while (q < i && q[1]) + { + if (*q != 1) + break; + q += q[1]; + } + if (q < i) + { + // reject + uint16_t n = 4; + i = p + l; + if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPV6CP))) + { + LOG(2, s, t, "Failed to send IPV6CP ConfigRej\n"); + return; + } + *q = ConfigRej; + p += 4; + while (p < i && p[1]) + { + if (*p != 1) + { + LOG(2, s, t, "IPV6CP reject %d\n", *p); + memcpy(q + n, p, p[1]); + n += p[1]; + } + p += p[1]; + } + *(uint16_t *) (q + 2) = htons(n); + LOG(4, s, t, "Sending ConfigRej\n"); + tunnelsend(b, n + (q - b), t); // send it + } + else + { + LOG(4, s, t, "Sending ConfigAck\n"); + *p = ConfigAck; + i = findppp(p, 1); // IP address + if (!i || i[1] != 10) { - LOG(2, 0, s, t, " Failed to send IPCP packet.\n"); + LOG(1, s, t, "No IP in IPV6CP request\n"); + STAT(tunnel_rx_errors); + return ; + } + if ((*(uint32_t *) (i + 2) != htonl(session[s].ip)) || + (*(uint32_t *) (i + 6) != 0)) + { + *(uint32_t *) (i + 2) = htonl(session[s].ip); + *(uint32_t *) (i + 6) = 0; + *p = ConfigNak; + LOG(4, s, t, + " No, a ConfigNak, client is " + "requesting IP - sending %s\n", + fmtaddr(htonl(session[s].ip), 0)); + } + if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPV6CP))) + { + LOG(2, s, t, " Failed to send IPV6CP packet.\n"); return; } tunnelsend(b, l + (q - b), t); // send it @@ -685,19 +968,19 @@ void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l) // // This MUST be called with at least 4 byte behind 'p'. // (i.e. this routine writes to p[-4]). -void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l) +void processipin(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) { - ipt ip; + in_addr_t ip; - CSTAT(call_processipin); + CSTAT(processipin); LOG_HEX(5, "IP", p, l); - ip = ntohl(*(u32 *)(p + 12)); + ip = ntohl(*(uint32_t *)(p + 12)); if (l > MAXETHER) { - LOG(1, ip, s, t, "IP packet too long %d\n", l); + LOG(1, s, t, "IP packet too long %d\n", l); STAT(tunnel_rx_errors); return ; } @@ -705,21 +988,29 @@ void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l) // no spoof (do sessionbyip to handled statically routed subnets) if (ip != session[s].ip && sessionbyip(htonl(ip)) != s) { - LOG(5, ip, s, t, "Dropping packet with spoofed IP %s\n", inet_toa(htonl(ip))); + LOG(5, s, t, "Dropping packet with spoofed IP %s\n", fmtaddr(htonl(ip), 0)); return; } + // run access-list if any + if (session[s].filter_in && !ip_filter(p, l, session[s].filter_in - 1)) + return; + // Add on the tun header p -= 4; - *(u32 *)p = htonl(0x00000800); + *(uint32_t *) p = htonl(PKTIP); l += 4; - if (session[s].tbf_in && !config->cluster_iam_master) { // Are we throttled and a slave? - master_throttle_packet(session[s].tbf_in, p, l); // Pass it to the master for handling. + // Are we throttled and a slave? + if (session[s].tbf_in && !config->cluster_iam_master) { + // Pass it to the master for handling. + master_throttle_packet(session[s].tbf_in, p, l); return; } - if (session[s].tbf_in && config->cluster_iam_master) { // Are we throttled and a master?? actually handle the throttled packets. + // Are we throttled and a master?? + if (session[s].tbf_in && config->cluster_iam_master) { + // Actually handle the throttled packets. tbf_queue_packet(session[s].tbf_in, p, l); return; } @@ -728,242 +1019,379 @@ void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l) if (tun_write(p, l) < 0) { STAT(tun_tx_errors); - LOG(0, 0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n", + LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n", l, strerror(errno), tunfd, p); return; } + p += 4; + l -= 4; + if (session[s].snoop_ip && session[s].snoop_port) { // Snooping this session - snoop_send_packet(p + 4, l - 4, session[s].snoop_ip, session[s].snoop_port); + snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port); } - session[s].cin += l - 4; - session[s].total_cin += l - 4; - sess_count[s].cin += l - 4; + increment_counter(&session[s].cin, &session[s].cin_wrap, l); + session[s].cin_delta += l; + session[s].pin++; + + sess_local[s].cin += l; + sess_local[s].pin++; + + eth_tx += l; + + STAT(tun_tx_packets); + INC_STAT(tun_tx_bytes, l); +} + +// process IPv6 packet received +// +// This MUST be called with at least 4 byte behind 'p'. +// (i.e. this routine writes to p[-4]). +void processipv6in(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) +{ + struct in6_addr ip; + in_addr_t ipv4; + + CSTAT(processipv6in); + + LOG_HEX(5, "IPv6", p, l); + + ip = *(struct in6_addr *) (p + 8); + ipv4 = ntohl(*(uint32_t *)(p + 16)); + if (l > MAXETHER) + { + LOG(1, s, t, "IP packet too long %d\n", l); + STAT(tunnel_rx_errors); + return ; + } + + // no spoof + if (ipv4 != session[s].ip && memcmp(&config->ipv6_prefix, &ip, 8) && sessionbyipv6(ip) != s) + { + char str[INET6_ADDRSTRLEN]; + LOG(5, s, t, "Dropping packet with spoofed IP %s\n", + inet_ntop(AF_INET6, &ip, str, INET6_ADDRSTRLEN)); + return; + } + + // Check if it's a Router Solicition message. + if (*(p + 6) == 58 && *(p + 7) == 255 && *(p + 24) == 0xFF && *(p + 25) == 2 && + *(uint32_t *)(p + 26) == 0 && *(uint32_t *)(p + 30) == 0 && + *(uint32_t *)(p + 34) == 0 && + *(p + 38) == 0 && *(p + 39) == 2 && *(p + 40) == 133) { + LOG(3, s, t, "Got IPv6 RS\n"); + send_ipv6_ra(t, s, &ip); + return; + } + + // Add on the tun header + p -= 4; + *(uint32_t *) p = htonl(PKTIPV6); + l += 4; + + // Are we throttled and a slave? + if (session[s].tbf_in && !config->cluster_iam_master) { + // Pass it to the master for handling. + master_throttle_packet(session[s].tbf_in, p, l); + return; + } + + // Are we throttled and a master?? + if (session[s].tbf_in && config->cluster_iam_master) { + // Actually handle the throttled packets. + tbf_queue_packet(session[s].tbf_in, p, l); + return; + } + + // send to ethernet + if (tun_write(p, l) < 0) + { + STAT(tun_tx_errors); + LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n", + l, strerror(errno), tunfd, p); + + return; + } + + p += 4; + l -= 4; + + if (session[s].snoop_ip && session[s].snoop_port) + { + // Snooping this session + snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port); + } + + increment_counter(&session[s].cin, &session[s].cin_wrap, l); + session[s].cin_delta += l; session[s].pin++; - eth_tx += l - 4; + + sess_local[s].cin += l; + sess_local[s].pin++; + + eth_tx += l; STAT(tun_tx_packets); - INC_STAT(tun_tx_bytes, l - 4); + INC_STAT(tun_tx_bytes, l); } // // Helper routine for the TBF filters. // Used to send queued data in from the user. // -void send_ipin(sessionidt s, u8 *buf, int len) +void send_ipin(sessionidt s, uint8_t *buf, int len) { LOG_HEX(5, "IP in throttled", buf, len); if (write(tunfd, buf, len) < 0) { STAT(tun_tx_errors); - LOG(0, 0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n", + LOG(0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n", len, strerror(errno), tunfd, buf); return; } + buf += 4; + len -= 4; + if (session[s].snoop_ip && session[s].snoop_port) { // Snooping this session - snoop_send_packet(buf + 4, len - 4, session[s].snoop_ip, session[s].snoop_port); + snoop_send_packet(buf, len, session[s].snoop_ip, session[s].snoop_port); } // Increment packet counters - session[s].cin += len - 4; - session[s].total_cin += len - 4; - sess_count[s].cin += len - 4; - + increment_counter(&session[s].cin, &session[s].cin_wrap, len); + session[s].cin_delta += len; session[s].pin++; - eth_tx += len - 4; + + sess_local[s].cin += len; + sess_local[s].pin++; + + eth_tx += len; STAT(tun_tx_packets); - INC_STAT(tun_tx_bytes, l - 4); + INC_STAT(tun_tx_bytes, len - 4); } // Process CCP messages -void processccp(tunnelidt t, sessionidt s, u8 *p, u16 l) +void processccp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l) { + uint8_t b[MAXCONTROL]; + uint8_t *q; - CSTAT(call_processccp); + CSTAT(processccp); LOG_HEX(5, "CCP", p, l); - if (l < 2 || (*p != ConfigReq && *p != TerminateReq)) - { - LOG(1, 0, s, t, "Unexpected CCP request code %d\n", *p); - STAT(tunnel_rx_errors); - return ; - } - // reject + switch (l > 1 ? *p : 0) { - u8 b[MAXCONTROL]; - u8 *q; - if (*p == ConfigReq) + case ConfigAck: + session[s].flags |= SF_CCP_ACKED; + return; + + case ConfigReq: + if (l < 6) // accept no compression { - if (l < 6) - { - *p = ConfigAck; // accept no compression - } - else - { - *p = ConfigRej; // reject - sendccp(t, s); - } + *p = ConfigAck; + break; } + + // compression requested--reject + *p = ConfigRej; + + // send CCP request for no compression for our end if not negotiated + if (!(session[s].flags & SF_CCP_ACKED)) + initccp(t, s); + + break; + + case TerminateReq: + *p = TerminateAck; + break; + + default: + if (l > 1) + LOG(1, s, t, "Unexpected CCP request code %d\n", *p); else - *p = TerminateAck; // close - if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPCCP))) - { - LOG(1,0,0,0, "Failed to send CCP packet.\n"); - return; - } - tunnelsend(b, l + (q - b), t); // send it + LOG(1, s, t, "Short CCP packet\n"); + + STAT(tunnel_rx_errors); + return; } + + if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPCCP))) + return; + + tunnelsend(b, l + (q - b), t); // send it } -// send a CHAP PP packet +// send a CHAP challenge void sendchap(tunnelidt t, sessionidt s) { - u8 b[MAXCONTROL]; - u16 r = session[s].radius; - u8 *q; + uint8_t b[MAXCONTROL]; + uint16_t r = sess_local[s].radius; + uint8_t *q; - CSTAT(call_sendchap); + CSTAT(sendchap); if (!r) { - LOG(1, 0, s, t, "No RADIUS to send challenge\n"); + LOG(1, s, t, "No RADIUS to send challenge\n"); STAT(tunnel_tx_errors); - return ; - } - LOG(1, 0, s, t, "Send CHAP challenge\n"); - { - // new challenge - int n; - for (n = 0; n < 15; n++) - radius[r].auth[n] = rand(); + return; } + + LOG(1, s, t, "Send CHAP challenge\n"); + radius[r].chap = 1; // CHAP not PAP radius[r].id++; if (radius[r].state != RADIUSCHAP) radius[r].try = 0; + radius[r].state = RADIUSCHAP; radius[r].retry = backoff(radius[r].try++); if (radius[r].try > 5) { - sessionshutdown(s, "Timeout CHAP"); + sessionshutdown(s, "CHAP timeout.", 3, 0); STAT(tunnel_tx_errors); return ; } q = makeppp(b, sizeof(b), 0, 0, t, s, PPPCHAP); - if (!q) - { - LOG(1, 0, s, t, "failed to send CHAP challenge.\n"); - return; - } + if (!q) return; + *q = 1; // challenge q[1] = radius[r].id; // ID - q[4] = 16; // length + q[4] = 16; // value size (size of challenge) memcpy(q + 5, radius[r].auth, 16); // challenge strcpy(q + 21, hostname); // our name - *(u16 *) (q + 2) = htons(strlen(hostname) + 21); // length + *(uint16_t *) (q + 2) = htons(strlen(hostname) + 21); // length tunnelsend(b, strlen(hostname) + 21 + (q - b), t); // send it } // fill in a L2TP message with a PPP frame, // copies existing PPP message and changes magic number if seen // returns start of PPP frame -u8 *makeppp(u8 *b, int size, u8 *p, int l, tunnelidt t, sessionidt s, u16 mtype) +uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, tunnelidt t, sessionidt s, uint16_t mtype) { - if (size < 12) - return NULL; // Need more space than this!! + if (size < 12) // Need more space than this!! + { + static int backtrace_count = 0; + LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size); + log_backtrace(backtrace_count, 5) + return NULL; + } - *(u16 *) (b + 0) = htons(0x0002); // L2TP with no options - *(u16 *) (b + 2) = htons(tunnel[t].far); // tunnel - *(u16 *) (b + 4) = htons(session[s].far); // session + *(uint16_t *) (b + 0) = htons(0x0002); // L2TP with no options + *(uint16_t *) (b + 2) = htons(tunnel[t].far); // tunnel + *(uint16_t *) (b + 4) = htons(session[s].far); // session b += 6; if (mtype == PPPLCP || !(session[s].l2tp_flags & SESSIONACFC)) { - *(u16 *) b = htons(0xFF03); // HDLC header + *(uint16_t *) b = htons(0xFF03); // HDLC header b += 2; } if (mtype < 0x100 && session[s].l2tp_flags & SESSIONPFC) *b++ = mtype; else { - *(u16 *) b = htons(mtype); + *(uint16_t *) b = htons(mtype); b += 2; } - if (l + 12 > size) { - LOG(3,0,0,0, "Would have overflowed the buffer in makeppp: size %d, len %d.\n", size, l); - return NULL; // Run out of room to hold the packet! + if (l + 12 > size) + { + static int backtrace_count = 0; + LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12); + log_backtrace(backtrace_count, 5) + return NULL; } + if (p && l) memcpy(b, p, l); + return b; } -// find a PPP option, returns point to option, or 0 if not found -u8 *findppp(u8 *b, u8 mtype) +static uint8_t *add_lcp_auth(uint8_t *b, int size, int authtype) { - u16 l = ntohs(*(u16 *) (b + 2)); - if (l < 4) + if ((authtype == AUTHCHAP && size < 5) || size < 4) return 0; - b += 4; - l -= 4; - while (l) + + *b++ = 3; // Authentication-Protocol + if (authtype == AUTHCHAP) { - if (l < b[1] || !b[1]) - return 0; // faulty - if (*b == mtype) - return b; - l -= b[1]; - b += b[1]; + *b++ = 5; // length + *(uint16_t *) b = htons(PPPCHAP); b += 2; + *b++ = 5; // MD5 } - return 0; + else if (authtype == AUTHPAP) + { + *b++ = 4; // length + *(uint16_t *) b = htons(PPPPAP); b += 2; + } + else + { + LOG(0, 0, 0, "add_lcp_auth called with unsupported auth type %d\n", authtype); + } + + return b; } -// Send initial LCP ConfigReq -void initlcp(tunnelidt t, sessionidt s) +// Send initial LCP ConfigReq for MRU, authentication type and magic no +void sendlcp(tunnelidt t, sessionidt s, int authtype) { - char b[500] = {0}, *q; + char b[500], *q, *l; - q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP); - if (!q) - { - LOG(1, 0, s, t, "Failed to send LCP ConfigReq.\n"); + if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP))) return; - } - LOG(4, 0, s, t, "Sending LCP ConfigReq for PAP\n"); - *q = ConfigReq; - *(u8 *)(q + 1) = (time_now % 255) + 1; // ID - *(u16 *)(q + 2) = htons(14); // Length - *(u8 *)(q + 4) = 5; - *(u8 *)(q + 5) = 6; - *(u32 *)(q + 6) = htonl(session[s].magic); - *(u8 *)(q + 10) = 3; - *(u8 *)(q + 11) = 4; - *(u16 *)(q + 12) = htons(PPPPAP); // PAP - tunnelsend(b, 12 + 14, t); + + LOG(4, s, t, "Sending LCP ConfigReq for %s\n", + authtype == AUTHCHAP ? "CHAP" : "PAP"); + + if (!session[s].mru) + session[s].mru = DEFAULT_MRU; + + l = q; + *l++ = ConfigReq; + *l++ = (time_now % 255) + 1; // ID + + l += 2; //Save space for length + + *l++ = 1; *l++ = 4; // Maximum-Receive-Unit (length 4) + *(uint16_t *) l = htons(session[s].mru); l += 2; + + l = add_lcp_auth(l, sizeof(b) - (l - b), authtype); + + *l++ = 5; *l++ = 6; // Magic-Number (length 6) + *(uint32_t *) l = htonl(session[s].magic); + l += 4; + + *(uint16_t *)(q + 2) = htons(l - q); // Length + + LOG_HEX(5, "PPPLCP", q, l - q); + tunnelsend(b, (l - b), t); } -// Send CCP reply -void sendccp(tunnelidt t, sessionidt s) +// Send CCP request for no compression +static void initccp(tunnelidt t, sessionidt s) { - char *q, b[500] = {0}; + char b[500], *q; + + if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPCCP))) + return; - q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPCCP); + LOG(4, s, t, "Sending CCP ConfigReq for no compression\n"); *q = ConfigReq; - *(u8 *)(q + 1) = (time_now % 255) + 1; // ID - *(u16 *)(q + 2) = htons(4); // Length + *(uint8_t *)(q + 1) = (time_now % 255) + 1; // ID + *(uint16_t *)(q + 2) = htons(4); // Length + LOG_HEX(5, "PPPCCP", q, 4); tunnelsend(b, (q - b) + 4 , t); } -