don't send 4 byte header when snooping v6 packets

[l2tpns.git] / l2tpns.c

diff --git a/l2tpns.c b/l2tpns.c
index 2073160..778dd24 100644 (file)
--- a/l2tpns.c
+++ b/l2tpns.c
@@ -4,7 +4,7 @@
 // Copyright (c) 2002 FireBrick (Andrews & Arnold Ltd / Watchfront Ltd) - GPL licenced
 // vim: sw=8 ts=8
 
 // Copyright (c) 2002 FireBrick (Andrews & Arnold Ltd / Watchfront Ltd) - GPL licenced
 // vim: sw=8 ts=8
 

-char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.79 2005-01-13 08:42:52 bodea Exp $";
+char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.80 2005-01-25 04:19:05 bodea Exp $";

 
 #include <arpa/inet.h>
 #include <assert.h>
 
 #include <arpa/inet.h>
 #include <assert.h>


@@ -19,6 +19,7 @@ char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.79 2005-01-13 08:42:52 bodea Exp
 #include <sys/mman.h>
 #include <netdb.h>
 #include <netinet/in.h>
 #include <sys/mman.h>
 #include <netdb.h>
 #include <netinet/in.h>

+#include <netinet/ip6.h>

 #include <stdarg.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <stdarg.h>
 #include <stdlib.h>
 #include <stdio.h>


@@ -62,9 +63,11 @@ int clifd = -1;                      // Socket listening for CLI connections.
 int snoopfd = -1;              // UDP file handle for sending out intercept data
 int *radfds = NULL;            // RADIUS requests file handles
 int ifrfd = -1;                        // File descriptor for routing, etc
 int snoopfd = -1;              // UDP file handle for sending out intercept data
 int *radfds = NULL;            // RADIUS requests file handles
 int ifrfd = -1;                        // File descriptor for routing, etc

+int ifr6fd = -1;               // File descriptor for IPv6 routing, etc

 static int rand_fd = -1;       // Random data source
 time_t basetime = 0;           // base clock
 char hostname[1000] = "";      // us.
 static int rand_fd = -1;       // Random data source
 time_t basetime = 0;           // base clock
 char hostname[1000] = "";      // us.

+static int tunidx;             // ifr_ifindex of tun device

 static uint32_t sessionid = 0; // session id for radius accounting
 static int syslog_log = 0;     // are we logging to syslog
 static FILE *log_stream = NULL;        // file handle for direct logging (i.e. direct into file, not via syslog).
 static uint32_t sessionid = 0; // session id for radius accounting
 static int syslog_log = 0;     // are we logging to syslog
 static FILE *log_stream = NULL;        // file handle for direct logging (i.e. direct into file, not via syslog).


@@ -75,6 +78,10 @@ struct cli_session_actions *cli_session_actions = NULL;      // Pending session chang
 struct cli_tunnel_actions *cli_tunnel_actions = NULL;  // Pending tunnel changes required by CLI
 
 static void *ip_hash[256];     // Mapping from IP address to session structures.
 struct cli_tunnel_actions *cli_tunnel_actions = NULL;  // Pending tunnel changes required by CLI
 
 static void *ip_hash[256];     // Mapping from IP address to session structures.

+struct ipv6radix {
+       int sess;
+       struct ipv6radix *branch;
+} ipv6_hash[256];              // Mapping from IPv6 address to session structures.

 
 // Traffic counters.
 static uint32_t udp_rx = 0, udp_rx_pkt = 0, udp_tx = 0;
 
 // Traffic counters.
 static uint32_t udp_rx = 0, udp_rx_pkt = 0, udp_tx = 0;


@@ -125,6 +132,7 @@ config_descriptt config_values[] = {
        CONFIG("cluster_interface", cluster_interface, STRING),
        CONFIG("cluster_hb_interval", cluster_hb_interval, INT),
        CONFIG("cluster_hb_timeout", cluster_hb_timeout, INT),
        CONFIG("cluster_interface", cluster_interface, STRING),
        CONFIG("cluster_hb_interval", cluster_hb_interval, INT),
        CONFIG("cluster_hb_timeout", cluster_hb_timeout, INT),

+       CONFIG("ipv6_prefix", ipv6_prefix, IPv6),

        { NULL, 0, 0, 0 },
 };
 
        { NULL, 0, 0, 0 },
 };
 


@@ -163,6 +171,7 @@ struct Tringbuffer *ringbuffer = NULL;
 
 static void cache_ipmap(in_addr_t ip, int s);
 static void uncache_ipmap(in_addr_t ip);
 
 static void cache_ipmap(in_addr_t ip, int s);
 static void uncache_ipmap(in_addr_t ip);

+static void cache_ipv6map(struct in6_addr ip, int prefixlen, int s);

 static void free_ip_address(sessionidt s);
 static void dump_acct_info(int all);
 static void sighup_handler(int sig);
 static void free_ip_address(sessionidt s);
 static void dump_acct_info(int all);
 static void sighup_handler(int sig);


@@ -421,11 +430,61 @@ static void routeset(sessionidt s, in_addr_t ip, in_addr_t mask, in_addr_t gw, i
        }
 }
 
        }
 }
 

+void route6set(sessionidt s, struct in6_addr ip, int prefixlen, int add)
+{
+       struct in6_rtmsg rt;
+       char ipv6addr[INET6_ADDRSTRLEN];
+
+       if (ifr6fd < 0)
+       {
+               LOG(0, 0, 0, "Asked to set IPv6 route, but IPv6 not setup.\n");
+               return;
+       }
+
+       memset(&rt, 0, sizeof(rt));
+
+       memcpy(&rt.rtmsg_dst, &ip, sizeof(struct in6_addr));
+       rt.rtmsg_dst_len = prefixlen;
+       rt.rtmsg_metric = 1;
+       rt.rtmsg_flags = RTF_UP;
+       rt.rtmsg_ifindex = tunidx;
+
+       LOG(1, 0, 0, "Route %s %s/%d\n",
+           add ? "add" : "del",
+           inet_ntop(AF_INET6, &ip, ipv6addr, INET6_ADDRSTRLEN),
+           prefixlen);
+
+       if (ioctl(ifr6fd, add ? SIOCADDRT : SIOCDELRT, (void *) &rt) < 0)
+               LOG(0, 0, 0, "route6set() error in ioctl: %s\n",
+                               strerror(errno));
+
+       // FIXME: need to add BGP routing (RFC2858)
+
+       if (s)
+       {
+               if (!add)       // Are we deleting a route?
+                       s = 0;  // Caching the session as '0' is the same as uncaching.
+
+               cache_ipv6map(ip, prefixlen, s);
+       }
+       
+       return;
+}
+
+// defined in linux/ipv6.h, but tricky to include from user-space
+// TODO: move routing to use netlink rather than ioctl
+struct in6_ifreq {
+       struct in6_addr ifr6_addr;
+       __u32 ifr6_prefixlen;
+       unsigned int ifr6_ifindex;
+};
+

 //
 // Set up TUN interface
 static void inittun(void)
 {
        struct ifreq ifr;
 //
 // Set up TUN interface
 static void inittun(void)
 {
        struct ifreq ifr;

+       struct in6_ifreq ifr6;

        struct sockaddr_in sin = {0};
        memset(&ifr, 0, sizeof(ifr));
        ifr.ifr_flags = IFF_TUN;
        struct sockaddr_in sin = {0};
        memset(&ifr, 0, sizeof(ifr));
        ifr.ifr_flags = IFF_TUN;


@@ -471,6 +530,42 @@ static void inittun(void)
                LOG(0, 0, 0, "Error setting tun flags: %s\n", strerror(errno));
                exit(1);
        }
                LOG(0, 0, 0, "Error setting tun flags: %s\n", strerror(errno));
                exit(1);
        }

+       if (ioctl(ifrfd, SIOCGIFINDEX, (void *) &ifr) < 0)
+       {
+               LOG(0, 0, 0, "Error getting tun ifindex: %s\n", strerror(errno));
+               exit(1);
+       }
+       tunidx = ifr.ifr_ifindex;
+
+       // Only setup IPv6 on the tun device if we have a configured prefix
+       if (config->ipv6_prefix.s6_addr[0] > 0) {
+               ifr6fd = socket(PF_INET6, SOCK_DGRAM, 0);
+
+               // Link local address is FE80::1
+               memset(&ifr6.ifr6_addr, 0, sizeof(ifr6.ifr6_addr));
+               ifr6.ifr6_addr.s6_addr[0] = 0xFE;
+               ifr6.ifr6_addr.s6_addr[1] = 0x80;
+               ifr6.ifr6_addr.s6_addr[15] = 1;
+               ifr6.ifr6_prefixlen = 64;
+               ifr6.ifr6_ifindex = ifr.ifr_ifindex;
+               if (ioctl(ifr6fd, SIOCSIFADDR, (void *) &ifr6) < 0)
+               {
+                       LOG(0, 0, 0, "Error setting tun IPv6 link local address:"
+                               " %s\n", strerror(errno));
+               }
+
+               // Global address is prefix::1
+               memset(&ifr6.ifr6_addr, 0, sizeof(ifr6.ifr6_addr));
+               ifr6.ifr6_addr = config->ipv6_prefix;
+               ifr6.ifr6_addr.s6_addr[15] = 1;
+               ifr6.ifr6_prefixlen = 64;
+               ifr6.ifr6_ifindex = ifr.ifr_ifindex;
+               if (ioctl(ifr6fd, SIOCSIFADDR, (void *) &ifr6) < 0)
+               {
+                       LOG(0, 0, 0, "Error setting tun IPv6 global address: %s\n",
+                               strerror(errno));
+               }
+       }

 }
 
 // set up UDP port
 }
 
 // set up UDP port


@@ -537,6 +632,32 @@ static int lookup_ipmap(in_addr_t ip)
        return (int) (intptr_t) d[(size_t) *a];
 }
 
        return (int) (intptr_t) d[(size_t) *a];
 }
 

+int lookup_ipv6map(struct in6_addr ip)
+{
+       struct ipv6radix *curnode;
+       int i;
+       int s;
+       char ipv6addr[INET6_ADDRSTRLEN];
+
+       curnode = &ipv6_hash[ip.s6_addr[0]];
+       i = 1;
+       s = curnode->sess;
+
+       while (s == 0 && i < 15 && curnode->branch != NULL)
+       {
+               curnode = &curnode->branch[ip.s6_addr[i]];
+               s = curnode->sess;
+               i++;
+       }
+
+       LOG(4, s, session[s].tunnel, "Looking up address %s and got %d\n",
+                       inet_ntop(AF_INET6, &ip, ipv6addr,
+                               INET6_ADDRSTRLEN),
+                       s);
+
+       return s;
+}
+

 sessionidt sessionbyip(in_addr_t ip)
 {
        int s = lookup_ipmap(ip);
 sessionidt sessionbyip(in_addr_t ip)
 {
        int s = lookup_ipmap(ip);


@@ -548,6 +669,25 @@ sessionidt sessionbyip(in_addr_t ip)
        return 0;
 }
 
        return 0;
 }
 

+sessionidt sessionbyipv6(struct in6_addr ip)
+{
+       int s;
+       CSTAT(sessionbyipv6);
+
+       if (!memcmp(&config->ipv6_prefix, &ip, 8) ||
+               (ip.s6_addr[0] == 0xFE && ip.s6_addr[1] == 0x80 &&
+                (ip.s6_addr16[1] == ip.s6_addr16[2] == ip.s6_addr16[3] == 0))) {
+               s = lookup_ipmap(*(in_addr_t *) &ip.s6_addr[8]);
+       } else {
+               s = lookup_ipv6map(ip);
+       }
+
+       if (s > 0 && s < MAXSESSION && session[s].tunnel)
+               return s;
+
+       return 0;
+}
+

 //
 // Take an IP address in HOST byte order and
 // add it to the sessionid by IP cache.
 //
 // Take an IP address in HOST byte order and
 // add it to the sessionid by IP cache.


@@ -587,6 +727,42 @@ static void uncache_ipmap(in_addr_t ip)
        cache_ipmap(ip, 0);     // Assign it to the NULL session.
 }
 
        cache_ipmap(ip, 0);     // Assign it to the NULL session.
 }
 

+static void cache_ipv6map(struct in6_addr ip, int prefixlen, int s)
+{
+       int i;
+       int bytes;
+       struct ipv6radix *curnode;
+       char ipv6addr[INET6_ADDRSTRLEN];
+
+       curnode = &ipv6_hash[ip.s6_addr[0]];
+
+       bytes = prefixlen >> 3;
+       i = 1;
+       while (i < bytes) {
+               if (curnode->branch == NULL)
+               {
+                       if (!(curnode->branch = calloc(256,
+                                       sizeof (struct ipv6radix))))
+                               return;
+               }
+               curnode = &curnode->branch[ip.s6_addr[i]];
+               i++;
+       }
+
+       curnode->sess = s;
+
+       if (s > 0)
+               LOG(4, s, session[s].tunnel, "Caching ip address %s/%d\n",
+                               inet_ntop(AF_INET6, &ip, ipv6addr, 
+                                       INET6_ADDRSTRLEN),
+                               prefixlen);
+       else if (s == 0)
+               LOG(4, 0, 0, "Un-caching ip address %s/%d\n",
+                               inet_ntop(AF_INET6, &ip, ipv6addr, 
+                                       INET6_ADDRSTRLEN),
+                               prefixlen);
+}
+

 //
 // CLI list to dump current ipcache.
 //
 //
 // CLI list to dump current ipcache.
 //


@@ -908,6 +1084,115 @@ static void processipout(uint8_t * buf, int len)
        sess_local[s].cout += len;      // To send to master..
 }
 
        sess_local[s].cout += len;      // To send to master..
 }
 

+// process outgoing (to tunnel) IPv6
+//
+void processipv6out(uint8_t * buf, int len)
+{
+       sessionidt s;
+       sessiont *sp;
+       tunnelidt t;
+       in_addr_t ip;
+       struct in6_addr ip6;
+
+       char *data = buf;       // Keep a copy of the originals.
+       int size = len;
+
+       uint8_t b[MAXETHER + 20];
+
+       CSTAT(processipv6out);
+
+       if (len < MIN_IP_SIZE)
+       {
+               LOG(1, 0, 0, "Short IPv6, %d bytes\n", len);
+               STAT(tunnel_tx_errors);
+               return;
+       }
+       if (len >= MAXETHER)
+       {
+               LOG(1, 0, 0, "Oversize IPv6 packet %d bytes\n", len);
+               STAT(tunnel_tx_errors);
+               return;
+       }
+
+       // Skip the tun header
+       buf += 4;
+       len -= 4;
+
+       // Got an IP header now
+       if (*(uint8_t *)(buf) >> 4 != 6)
+       {
+               LOG(1, 0, 0, "IP: Don't understand anything except IPv6\n");
+               return;
+       }
+
+       ip6 = *(struct in6_addr *)(buf+24);
+       s = sessionbyipv6(ip6);
+
+       if (s == 0)
+       {
+               ip = *(uint32_t *)(buf + 32);
+               s = sessionbyip(ip);
+       }
+       
+       if (s == 0)
+       {
+               // Is this a packet for a session that doesn't exist?
+               static int rate = 0;    // Number of ICMP packets we've sent this second.
+               static int last = 0;    // Last time we reset the ICMP packet counter 'rate'.
+
+               if (last != time_now)
+               {
+                       last = time_now;
+                       rate = 0;
+               }
+
+               if (rate++ < config->icmp_rate) // Only send a max of icmp_rate per second.
+               {
+                       // FIXME: Should send icmp6 host unreachable
+               }
+               return;
+       }
+       t = session[s].tunnel;
+       sp = &session[s];
+
+       // FIXME: add DoS prevention/filters?
+
+       if (sp->tbf_out)
+       {
+               // Are we throttling this session?
+               if (config->cluster_iam_master)
+                       tbf_queue_packet(sp->tbf_out, data, size);
+               else
+                       master_throttle_packet(sp->tbf_out, data, size);
+               return;
+       }
+       else if (sp->walled_garden && !config->cluster_iam_master)
+       {
+               // We are walled-gardening this
+               master_garden_packet(s, data, size);
+               return;
+       }
+
+       LOG(5, s, t, "Ethernet -> Tunnel (%d bytes)\n", len);
+
+       // Add on L2TP header
+       {
+               uint8_t *p = makeppp(b, sizeof(b), buf, len, t, s, PPPIPV6);
+               if (!p) return;
+               tunnelsend(b, len + (p-b), t); // send it...
+       }
+
+       // Snooping this session, send it to intercept box
+       if (sp->snoop_ip && sp->snoop_port)
+               snoop_send_packet(buf, len, sp->snoop_ip, sp->snoop_port);
+
+       sp->cout += len; // byte count
+       sp->total_cout += len; // byte count
+       sp->pout++;
+       udp_tx += len;
+       sess_local[s].cout += len;      // To send to master..
+}
+

 //
 // Helper routine for the TBF filters.
 // Used to send queued data in to the user!
 //
 // Helper routine for the TBF filters.
 // Used to send queued data in to the user!


@@ -1215,6 +1500,10 @@ void sessionshutdown(sessionidt s, char *reason)
                }
                else
                        free_ip_address(s);
                }
                else
                        free_ip_address(s);

+
+               // unroute IPv6, if setup
+               if (session[s].flags & SF_IPV6_ROUTED)
+                       route6set(s, session[s].ipv6route, session[s].ipv6prefixlen, 0);

        }
 
        if (session[s].throttle_in || session[s].throttle_out) // Unthrottle if throttled.
        }
 
        if (session[s].throttle_in || session[s].throttle_out) // Unthrottle if throttled.


@@ -1276,6 +1565,30 @@ void sendipcp(tunnelidt t, sessionidt s)
 
        tunnelsend(buf, 10 + (q - buf), t); // send it
        session[s].flags &= ~SF_IPCP_ACKED;     // Clear flag.
 
        tunnelsend(buf, 10 + (q - buf), t); // send it
        session[s].flags &= ~SF_IPCP_ACKED;     // Clear flag.

+
+       // If we have an IPv6 prefix length configured, assume we should
+       // try to negotiate an IPv6 session as well. Unless we've had a
+       // (N)ACK for IPV6CP.
+       if (config->ipv6_prefix.s6_addr[0] > 0 && 
+                       !(session[s].flags & SF_IPV6CP_ACKED) &&
+                       !(session[s].flags & SF_IPV6_NACKED))
+       {
+               q = makeppp(buf,sizeof(buf), 0, 0, t, s, PPPIPV6CP);
+               if (!q) return;
+
+               *q = ConfigReq;
+               q[1] = r << RADIUS_SHIFT;               // ID, don't care, we
+                                                       // only send one type
+                                                       // of request
+               *(uint16_t *) (q + 2) = htons(14);
+               q[4] = 1;
+               q[5] = 10;
+               *(uint32_t *) (q + 6) = 0;              // We'll be prefix::1
+               *(uint32_t *) (q + 10) = 0;
+               q[13] = 1;
+
+               tunnelsend(buf, 14 + (q - buf), t);     // send it
+       }

 }
 
 // kill a session now
 }
 
 // kill a session now


@@ -2037,6 +2350,19 @@ void processudp(uint8_t * buf, int len, struct sockaddr_in *addr)
                        if (!config->cluster_iam_master) { master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port); return; }
                        processipcp(t, s, p, l);
                }
                        if (!config->cluster_iam_master) { master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port); return; }
                        processipcp(t, s, p, l);
                }

+               else if (prot == PPPIPV6CP)
+               {
+                       if (config->ipv6_prefix.s6_addr[0] > 0)
+                       {
+                               session[s].last_packet = time_now;
+                               if (!config->cluster_iam_master) { master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port); return; }
+                               processipv6cp(t, s, p, l);
+                       }
+                       else
+                       {
+                               LOG(1, s, t, "IPv6 not configured; ignoring IPv6CP\n");
+                       }
+               }

                else if (prot == PPPCCP)
                {
                        session[s].last_packet = time_now;
                else if (prot == PPPCCP)
                {
                        session[s].last_packet = time_now;


@@ -2060,6 +2386,28 @@ void processudp(uint8_t * buf, int len, struct sockaddr_in *addr)
 
                        processipin(t, s, p, l);
                }
 
                        processipin(t, s, p, l);
                }

+               else if (prot == PPPIPV6)
+               {
+                       if (!config->ipv6_prefix.s6_addr[0] > 0)
+                       {
+                               LOG(1, s, t, "IPv6 not configured; yet received IPv6 packet. Ignoring.\n");
+                               return;
+                       }
+                       if (session[s].die)
+                       {
+                               LOG(4, s, t, "Session %d is closing.  Don't process PPP packets\n", s);
+                               return;              // closing session, PPP not processed
+                       }
+
+                       session[s].last_packet = time_now;
+                       if (session[s].walled_garden && !config->cluster_iam_master)
+                       {
+                               master_forward_packet(buf, len, addr->sin_addr.s_addr, addr->sin_port);
+                               return;
+                       }
+
+                       processipv6in(t, s, p, l);
+               }

                else
                {
                        STAT(tunnel_rx_errors);
                else
                {
                        STAT(tunnel_rx_errors);


@@ -2088,6 +2436,10 @@ static void processtun(uint8_t * buf, int len)
 
        if (*(uint16_t *) (buf + 2) == htons(PKTIP)) // IPv4
                processipout(buf, len);
 
        if (*(uint16_t *) (buf + 2) == htons(PKTIP)) // IPv4
                processipout(buf, len);

+       else if (*(uint16_t *) (buf + 2) == htons(PKTIPV6) // IPV6
+           && config->ipv6_prefix.s6_addr[0] > 0)
+               processipv6out(buf, len);
+

        // Else discard.
 }
 
        // Else discard.
 }
 


@@ -3897,6 +4249,7 @@ int sessionsetup(tunnelidt t, sessionidt s)
                // convered by a Framed-Route.  Anything else is part
                // of the IP address pool and is already routed, it
                // just needs to be added to the IP cache.
                // convered by a Framed-Route.  Anything else is part
                // of the IP address pool and is already routed, it
                // just needs to be added to the IP cache.

+               // IPv6 route setup is done in ppp.c, when IPV6CP is acked.

                if (session[s].ip_pool_index == -1) // static ip
                {
                        if (!routed) routeset(s, session[s].ip, 0, 0, 1);
                if (session[s].ip_pool_index == -1) // static ip
                {
                        if (!routed) routeset(s, session[s].ip, 0, 0, 1);


@@ -4019,6 +4372,10 @@ int load_session(sessionidt s, sessiont *new)
                }
        }
 
                }
        }
 

+       // check v6 routing
+       if (new->flags & SF_IPV6_ROUTED && !(session[s].flags & SF_IPV6_ROUTED))
+                   route6set(s, new->ipv6route, new->ipv6prefixlen, 1);
+

        // check filters
        if (new->filter_in && (new->filter_in > MAXFILTER || !ip_filters[new->filter_in - 1].name[0]))
        {
        // check filters
        if (new->filter_in && (new->filter_in > MAXFILTER || !ip_filters[new->filter_in - 1].name[0]))
        {