Introducing the Big Tinc Lock.
[tinc] / src / net_packet.c
index b35f72d..a985390 100644 (file)
@@ -3,6 +3,7 @@
     Copyright (C) 1998-2005 Ivo Timmermans,
                   2000-2010 Guus Sliepen <guus@tinc-vpn.org>
                   2010      Timothy Redaelli <timothy@redaelli.eu>
+                  2010      Brandon Black <blblack@gmail.com>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
 #include LZO1X_H
 #endif
 
-#include "avl_tree.h"
+#include "splay_tree.h"
+#include "cipher.h"
 #include "conf.h"
 #include "connection.h"
+#include "crypto.h"
+#include "digest.h"
 #include "device.h"
 #include "ethernet.h"
-#include "event.h"
 #include "graph.h"
 #include "list.h"
 #include "logger.h"
@@ -69,13 +72,13 @@ unsigned replaywin = 16;
 // mtuprobes ==    32: send 1 burst, sleep pingtimeout second
 // mtuprobes ==    33: no response from other side, restart PMTU discovery process
 
-void send_mtu_probe(node_t *n) {
+static void send_mtu_probe_handler(void *data) {
+       node_t *n = data;
        vpn_packet_t packet;
        int len, i;
        int timeout = 1;
        
        n->mtuprobes++;
-       n->mtuevent = NULL;
 
        if(!n->status.reachable || !n->status.validkey) {
                ifdebug(TRAFFIC) logger(LOG_INFO, "Trying to send MTU probe to unreachable or rekeying node %s (%s)", n->name, n->hostname);
@@ -123,7 +126,7 @@ void send_mtu_probe(node_t *n) {
                        len = 64;
                
                memset(packet.data, 0, 14);
-               RAND_pseudo_bytes(packet.data + 14, len - 14);
+               randomize(packet.data + 14, len - 14);
                packet.len = len;
                packet.priority = 0;
 
@@ -133,11 +136,15 @@ void send_mtu_probe(node_t *n) {
        }
 
 end:
-       n->mtuevent = new_event();
-       n->mtuevent->handler = (event_handler_t)send_mtu_probe;
-       n->mtuevent->data = n;
-       n->mtuevent->time = now + timeout;
-       event_add(n->mtuevent);
+       n->mtuevent.time = time(NULL) + timeout;
+       event_add(&n->mtuevent);
+}
+
+void send_mtu_probe(node_t *n) {
+       event_del(&n->mtuevent);
+       n->mtuevent.handler = send_mtu_probe_handler;
+       n->mtuevent.data = n;
+       send_mtu_probe_handler(n);
 }
 
 void mtu_probe_h(node_t *n, vpn_packet_t *packet, length_t len) {
@@ -224,15 +231,11 @@ static void receive_packet(node_t *n, vpn_packet_t *packet) {
        route(n, packet);
 }
 
-static bool try_mac(const node_t *n, const vpn_packet_t *inpkt) {
-       unsigned char hmac[EVP_MAX_MD_SIZE];
-
-       if(!n->indigest || !n->inmaclength || !n->inkey || inpkt->len < sizeof inpkt->seqno + n->inmaclength)
+static bool try_mac(node_t *n, const vpn_packet_t *inpkt) {
+       if(!digest_active(&n->indigest) || inpkt->len < sizeof inpkt->seqno + digest_length(&n->indigest))
                return false;
 
-       HMAC(n->indigest, n->inkey, n->inkeylength, (unsigned char *) &inpkt->seqno, inpkt->len - n->inmaclength, (unsigned char *)hmac, NULL);
-
-       return !memcmp(hmac, (char *) &inpkt->seqno + inpkt->len - n->inmaclength, n->inmaclength);
+       return digest_verify(&n->indigest, &inpkt->seqno, inpkt->len - n->indigest.maclength, (const char *)&inpkt->seqno + inpkt->len - n->indigest.maclength);
 }
 
 static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
@@ -240,11 +243,10 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
        vpn_packet_t *pkt[] = { &pkt1, &pkt2, &pkt1, &pkt2 };
        int nextpkt = 0;
        vpn_packet_t *outpkt = pkt[0];
-       int outlen, outpad;
-       unsigned char hmac[EVP_MAX_MD_SIZE];
+       size_t outlen;
        int i;
 
-       if(!n->inkey) {
+       if(!cipher_active(&n->incipher)) {
                ifdebug(TRAFFIC) logger(LOG_DEBUG, "Got packet from %s (%s) but he hasn't got our key yet",
                                        n->name, n->hostname);
                return;
@@ -252,7 +254,7 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 
        /* Check packet length */
 
-       if(inpkt->len < sizeof(inpkt->seqno) + n->inmaclength) {
+       if(inpkt->len < sizeof inpkt->seqno + digest_length(&n->indigest)) {
                ifdebug(TRAFFIC) logger(LOG_DEBUG, "Got too short packet from %s (%s)",
                                        n->name, n->hostname);
                return;
@@ -260,47 +262,43 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
 
        /* Check the message authentication code */
 
-       if(n->indigest && n->inmaclength) {
-               inpkt->len -= n->inmaclength;
-               HMAC(n->indigest, n->inkey, n->inkeylength,
-                        (unsigned char *) &inpkt->seqno, inpkt->len, (unsigned char *)hmac, NULL);
-
-               if(memcmp(hmac, (char *) &inpkt->seqno + inpkt->len, n->inmaclength)) {
-                       ifdebug(TRAFFIC) logger(LOG_DEBUG, "Got unauthenticated packet from %s (%s)",
-                                          n->name, n->hostname);
+       if(digest_active(&n->indigest)) {
+               inpkt->len -= n->indigest.maclength;
+               if(!digest_verify(&n->indigest, &inpkt->seqno, inpkt->len, (const char *)&inpkt->seqno + inpkt->len)) {
+                       ifdebug(TRAFFIC) logger(LOG_DEBUG, "Got unauthenticated packet from %s (%s)", n->name, n->hostname);
                        return;
                }
        }
-
        /* Decrypt the packet */
 
-       if(n->incipher) {
+       if(cipher_active(&n->incipher)) {
                outpkt = pkt[nextpkt++];
+               outlen = MAXSIZE;
 
-               if(!EVP_DecryptInit_ex(&n->inctx, NULL, NULL, NULL, NULL)
-                               || !EVP_DecryptUpdate(&n->inctx, (unsigned char *) &outpkt->seqno, &outlen,
-                                       (unsigned char *) &inpkt->seqno, inpkt->len)
-                               || !EVP_DecryptFinal_ex(&n->inctx, (unsigned char *) &outpkt->seqno + outlen, &outpad)) {
-                       ifdebug(TRAFFIC) logger(LOG_DEBUG, "Error decrypting packet from %s (%s): %s",
-                                               n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL));
+               if(!cipher_decrypt(&n->incipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
+                       ifdebug(TRAFFIC) logger(LOG_DEBUG, "Error decrypting packet from %s (%s)", n->name, n->hostname);
                        return;
                }
                
-               outpkt->len = outlen + outpad;
+               outpkt->len = outlen;
                inpkt = outpkt;
        }
 
        /* Check the sequence number */
 
-       inpkt->len -= sizeof(inpkt->seqno);
+       inpkt->len -= sizeof inpkt->seqno;
        inpkt->seqno = ntohl(inpkt->seqno);
 
        if(replaywin) {
                if(inpkt->seqno != n->received_seqno + 1) {
                        if(inpkt->seqno >= n->received_seqno + replaywin * 8) {
+                               if(n->farfuture++ < replaywin >> 2) {
+                                       logger(LOG_WARNING, "Packet from %s (%s) is %d seqs in the future, dropped (%u)",
+                                               n->name, n->hostname, inpkt->seqno - n->received_seqno - 1, n->farfuture);
+                                       return;
+                               }
                                logger(LOG_WARNING, "Lost %d packets from %s (%s)",
                                                inpkt->seqno - n->received_seqno - 1, n->name, n->hostname);
-                               
                                memset(n->late, 0, replaywin);
                        } else if (inpkt->seqno <= n->received_seqno) {
                                if((n->received_seqno >= replaywin * 8 && inpkt->seqno <= n->received_seqno - replaywin * 8) || !(n->late[(inpkt->seqno / 8) % replaywin] & (1 << inpkt->seqno % 8))) {
@@ -313,7 +311,8 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
                                        n->late[(i / 8) % replaywin] |= 1 << i % 8;
                        }
                }
-       
+
+               n->farfuture = 0;
                n->late[(inpkt->seqno / 8) % replaywin] &= ~(1 << inpkt->seqno % 8);
        }
 
@@ -321,7 +320,7 @@ static void receive_udppacket(node_t *n, vpn_packet_t *inpkt) {
                n->received_seqno = inpkt->seqno;
                        
        if(n->received_seqno > MAX_SEQNO)
-               keyexpires = 0;
+               regenerate_key();
 
        /* Decompress the packet */
 
@@ -369,7 +368,7 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
        int nextpkt = 0;
        vpn_packet_t *outpkt;
        int origlen;
-       int outlen, outpad;
+       size_t outlen;
 #if defined(SOL_IP) && defined(IP_TOS)
        static int priority = 0;
 #endif
@@ -384,6 +383,8 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
        /* Make sure we have a valid key */
 
        if(!n->status.validkey) {
+               time_t now = time(NULL);
+
                ifdebug(TRAFFIC) logger(LOG_INFO,
                                   "No valid key known yet for %s (%s), forwarding via TCP",
                                   n->name, n->hostname);
@@ -431,32 +432,28 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
        /* Add sequence number */
 
        inpkt->seqno = htonl(++(n->sent_seqno));
-       inpkt->len += sizeof(inpkt->seqno);
+       inpkt->len += sizeof inpkt->seqno;
 
        /* Encrypt the packet */
 
-       if(n->outcipher) {
+       if(cipher_active(&n->outcipher)) {
                outpkt = pkt[nextpkt++];
+               outlen = MAXSIZE;
 
-               if(!EVP_EncryptInit_ex(&n->outctx, NULL, NULL, NULL, NULL)
-                               || !EVP_EncryptUpdate(&n->outctx, (unsigned char *) &outpkt->seqno, &outlen,
-                                       (unsigned char *) &inpkt->seqno, inpkt->len)
-                               || !EVP_EncryptFinal_ex(&n->outctx, (unsigned char *) &outpkt->seqno + outlen, &outpad)) {
-                       ifdebug(TRAFFIC) logger(LOG_ERR, "Error while encrypting packet to %s (%s): %s",
-                                               n->name, n->hostname, ERR_error_string(ERR_get_error(), NULL));
+               if(!cipher_encrypt(&n->outcipher, &inpkt->seqno, inpkt->len, &outpkt->seqno, &outlen, true)) {
+                       ifdebug(TRAFFIC) logger(LOG_ERR, "Error while encrypting packet to %s (%s)", n->name, n->hostname);
                        goto end;
                }
 
-               outpkt->len = outlen + outpad;
+               outpkt->len = outlen;
                inpkt = outpkt;
        }
 
        /* Add the message authentication code */
 
-       if(n->outdigest && n->outmaclength) {
-               HMAC(n->outdigest, n->outkey, n->outkeylength, (unsigned char *) &inpkt->seqno,
-                        inpkt->len, (unsigned char *) &inpkt->seqno + inpkt->len, NULL);
-               inpkt->len += n->outmaclength;
+       if(digest_active(&n->outdigest)) {
+               digest_create(&n->outdigest, &inpkt->seqno, inpkt->len, (char *)&inpkt->seqno + inpkt->len);
+               inpkt->len += digest_length(&n->outdigest);
        }
 
        /* Determine which socket we have to use */
@@ -475,7 +472,7 @@ static void send_udppacket(node_t *n, vpn_packet_t *origpkt) {
           && listen_socket[sock].sa.sa.sa_family == AF_INET) {
                priority = origpriority;
                ifdebug(TRAFFIC) logger(LOG_DEBUG, "Setting outgoing packet priority to %d", priority);
-               if(setsockopt(listen_socket[sock].udp, SOL_IP, IP_TOS, &priority, sizeof(priority)))    /* SO_PRIORITY doesn't seem to work */
+               if(setsockopt(listen_socket[sock].udp, SOL_IP, IP_TOS, &priority, sizeof priority))     /* SO_PRIORITY doesn't seem to work */
                        logger(LOG_ERR, "System call `%s' failed: %s", "setsockopt", strerror(errno));
        }
 #endif
@@ -532,7 +529,7 @@ void send_packet(const node_t *n, vpn_packet_t *packet) {
 /* Broadcast a packet using the minimum spanning tree */
 
 void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
-       avl_node_t *node;
+       splay_node_t *node;
        connection_t *c;
 
        ifdebug(TRAFFIC) logger(LOG_INFO, "Broadcasting packet of %d bytes from %s (%s)",
@@ -556,65 +553,78 @@ void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
 }
 
 static node_t *try_harder(const sockaddr_t *from, const vpn_packet_t *pkt) {
-       avl_node_t *node;
-       edge_t *e;
-       node_t *n = NULL;
+       splay_node_t *node;
+       node_t *n, *found = NULL;
        static time_t last_hard_try = 0;
+       time_t now = time(NULL);
 
-       for(node = edge_weight_tree->head; node; node = node->next) {
-               e = node->data;
-
-               if(sockaddrcmp_noport(from, &e->address)) {
-                       if(last_hard_try == now)
-                               continue;
-                       last_hard_try = now;
-               }
+       if(last_hard_try == now)
+               return NULL;
+       else
+               last_hard_try = now;
 
-               if(!n)
-                       n = e->to;
+       for(node = node_tree->head; node; node = node->next) {
+               n = node->data;
 
-               if(!try_mac(e->to, pkt))
+               if(n == myself || !n->status.reachable || !digest_active(&n->indigest))
                        continue;
 
-               n = e->to;
-               break;
+               if(try_mac(n, pkt)) {
+                       found = n;
+                       break;
+               }
        }
 
-       return n;
+       return found;
 }
 
-void handle_incoming_vpn_data(int sock) {
+void handle_incoming_vpn_data(void *arg) {
+       listen_socket_t *l = arg;
        vpn_packet_t pkt;
        char *hostname;
        sockaddr_t from;
-       socklen_t fromlen = sizeof(from);
+       socklen_t fromlen = sizeof from;
        node_t *n;
+       int len;
 
-       pkt.len = recvfrom(sock, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
+       while(true) {
+               len = recvfrom(l->udp, (char *) &pkt.seqno, MAXSIZE, 0, &from.sa, &fromlen);
 
-       if(pkt.len < 0) {
-               if(!sockwouldblock(sockerrno))
+               if(len <= 0 || len > MAXSIZE) {
                        logger(LOG_ERR, "Receiving packet failed: %s", sockstrerror(sockerrno));
-               return;
-       }
+                       return;
+               }
 
-       sockaddrunmap(&from);           /* Some braindead IPv6 implementations do stupid things. */
+               pkt.len = len;
 
-       n = lookup_node_udp(&from);
+               sockaddrunmap(&from);           /* Some braindead IPv6 implementations do stupid things. */
 
-       if(!n) {
-               n = try_harder(&from, &pkt);
-               if(n)
-                       update_node_udp(n, &from);
-               else ifdebug(PROTOCOL) {
-                       hostname = sockaddr2hostname(&from);
-                       logger(LOG_WARNING, "Received UDP packet from unknown source %s", hostname);
-                       free(hostname);
-                       return;
+               mutex_lock(&mutex);
+               n = lookup_node_udp(&from);
+
+               if(!n) {
+                       n = try_harder(&from, &pkt);
+                       if(n)
+                               update_node_udp(n, &from);
                }
-               else
-                       return;
+
+               if(n) {
+                       receive_udppacket(n, &pkt);
+               } else {
+                       ifdebug(PROTOCOL) {
+                               hostname = sockaddr2hostname(&from);
+                               logger(LOG_WARNING, "Received UDP packet from unknown source %s", hostname);
+                               free(hostname);
+                       }
+               }
+
+               mutex_unlock(&mutex);
        }
+}
+
+void handle_device_data(int sock, short events, void *data) {
+       vpn_packet_t packet;
 
-       receive_udppacket(n, &pkt);
+       if(read_packet(&packet))
+               route(myself, &packet);
 }