Respect RFC 3927 more, regarding times and conflicts.

diff --git a/net.c b/net.c
index f0e26e3de67623274052dec6aaa8c3c1e7644201..762de76ee23cac8723121ae8447db2588345dbe8 100644 (file)
--- a/net.c
+++ b/net.c
@@ -591,12 +591,6 @@ valid_udp_packet(const uint8_t *data)
 }
 
 #ifdef ENABLE_ARP
-/* These are really for IPV4LL */
-#define NPROBES                 3
-#define PROBE_INTERVAL          200
-#define NCLAIMS                 2
-#define CLAIM_INTERVAL          200
-
 static int
 send_arp(const struct interface *iface, int op, struct in_addr sip,
         const unsigned char *taddr, struct in_addr tip)
@@ -640,9 +634,12 @@ arp_claim(struct interface *iface, struct in_addr address)
 {
        struct arphdr reply;
        uint8_t arp_reply[sizeof(reply) + 2 * 4 /* IPv4 */ + 2 * 8 /* EUI64 */];
-       struct in_addr reply_ipv4;
-       struct ether_addr reply_mac;
-       long timeout = 0;
+       uint8_t *p;
+       struct ether_addr reply_smac;
+       struct in_addr reply_sipv4;
+       struct ether_addr reply_tmac;
+       struct in_addr reply_tipv4;
+       long timeout;
        int retval = -1;
        int nprobes = 0;
        int nclaims = 0;
@@ -667,7 +664,12 @@ arp_claim(struct interface *iface, struct in_addr address)
                       "checking %s is available on attached networks",
                       inet_ntoa(address));
 
-       if (!open_socket(iface, ETHERTYPE_ARP)) {
+       timeout = arc4random() % PROBE_WAIT;
+       if (get_time(&stopat) != 0)
+               return -1;
+       stopat.tv_usec += timeout * 1000;
+
+       if (open_socket(iface, ETHERTYPE_ARP) == -1) {
                logger (LOG_ERR, "open_socket: %s", strerror(errno));
                return -1;
        }
@@ -681,19 +683,28 @@ arp_claim(struct interface *iface, struct in_addr address)
 
                /* Only poll if we have a timeout */
                if (timeout > 0) {
+                       /* Obey IPV4LL timings, but make us faster for
+                        * routeable addresses */
+                       if (IN_LINKLOCAL(htonl(address.s_addr)))
+                               timeout *= 1000;
+                       else
+                               timeout *= 200;
                        s = poll(fds, 2, timeout);
                        if (s == -1) {
                                if (errno != EINTR)
-                                       logger(LOG_ERR, "poll: `%s'", strerror(errno));
+                                       logger(LOG_ERR, "poll: `%s'",
+                                              strerror(errno));
                                break;
                        }
                }
 
                /* Timed out */
                if (s == 0) {
-                       if (nprobes < NPROBES) {
-                               nprobes ++;
-                               timeout = PROBE_INTERVAL;
+                       if (nprobes < PROBE_NUM) {
+                               nprobes++;
+                               timeout = (arc4random() %
+                                          (PROBE_MAX - PROBE_MIN)) +
+                                         PROBE_MIN;
                                logger(LOG_DEBUG, "sending ARP probe #%d",
                                       nprobes);
                                if (send_arp(iface, ARPOP_REQUEST,
@@ -703,12 +714,12 @@ arp_claim(struct interface *iface, struct in_addr address)
 
                                /* IEEE1394 cannot set ARP target address
                                 * according to RFC2734 */
-                               if (nprobes >= NPROBES &&
+                               if (nprobes >= PROBE_NUM &&
                                    iface->family == ARPHRD_IEEE1394)
-                                       nclaims = NCLAIMS;
-                       } else if (nclaims < NCLAIMS) {
-                               nclaims ++;
-                               timeout = CLAIM_INTERVAL;
+                                       nclaims = ANNOUNCE_NUM;
+                       } else if (nclaims < ANNOUNCE_NUM) {
+                               nclaims++;
+                               timeout = ANNOUNCE_INTERVAL;
                                logger(LOG_DEBUG, "sending ARP claim #%d",
                                       nclaims);
                                if (send_arp(iface, ARPOP_REQUEST,
@@ -724,7 +735,7 @@ arp_claim(struct interface *iface, struct in_addr address)
                        /* Setup our stop time */
                        if (get_time(&stopat) != 0)
                                break;
-                       stopat.tv_usec += timeout;
+                       stopat.tv_usec += timeout * 1000;
                        continue;
                }
 
@@ -752,43 +763,46 @@ arp_claim(struct interface *iface, struct in_addr address)
                                break;
 
                        memcpy(&reply, arp_reply, sizeof(reply));
-                       /* Only these types are recognised */
-                       if (reply.ar_op != htons(ARPOP_REPLY))
-                               continue;
                        /* Protocol must be IP. */
                        if (reply.ar_pro != htons(ETHERTYPE_IP))
                                continue;
-                       if (reply.ar_pln != sizeof(reply_ipv4))
+                       if (reply.ar_pln != sizeof(reply_sipv4))
                                continue;
                        if ((size_t)bytes < sizeof(reply) + 2 *
                            (4 + reply.ar_hln) ||
                            reply.ar_hln > 8)
                                continue;
 
-                       memcpy(&reply_mac,
-                              arp_reply + sizeof(reply), reply.ar_hln);
-                       memcpy(&reply_ipv4,
-                              arp_reply + sizeof(reply) + reply.ar_hln,
-                              reply.ar_pln);
-
-                       /* Ensure the ARP reply is for the our address */
-                       if (reply_ipv4.s_addr != address.s_addr)
-                               continue;
-
-                       /* Some systems send a reply back from our hwaddress,
-                        * which is wierd */
-                       if (reply.ar_hln == iface->hwlen &&
-                           memcmp(&reply_mac, iface->hwaddr,
-                                  iface->hwlen) == 0)
+                       /* Only these types are recognised */
+                       if (reply.ar_op != htons(ARPOP_REPLY) &&
+                           reply.ar_op != htons(ARPOP_REQUEST))
                                continue;
 
-                       logger(LOG_ERR, "ARPOP_REPLY received from %s (%s)",
-                              inet_ntoa(reply_ipv4),
-                              hwaddr_ntoa((unsigned char *)&reply_mac,
-                                          (size_t)reply.ar_hln));
-                       errno = EEXIST;
-                       retval = -1;
-                       goto eexit;
+                       /* Copy out the ARP packet */
+                       p = arp_reply + sizeof(reply);
+                       memcpy(&reply_smac, p, reply.ar_hln);
+                       p += reply.ar_hln;
+                       memcpy(&reply_sipv4, p, reply.ar_pln);
+                       p += reply.ar_pln;
+                       memcpy(&reply_tmac, p, reply.ar_hln);
+                       p += reply.ar_hln;
+                       memcpy(&reply_tipv4, p, reply.ar_pln);
+
+                       /* Check for conflict */
+                       if (reply_sipv4.s_addr == address.s_addr ||
+                           (reply_tipv4.s_addr == address.s_addr &&
+                            reply.ar_op == htons(ARPOP_REQUEST) &&
+                            memcmp(&reply_smac, iface->hwaddr,
+                                   iface->hwlen) != 0))
+                       {
+                               logger(LOG_ERR, "hardware address %s claims %s",
+                                      hwaddr_ntoa((unsigned char *)&reply_smac,
+                                                  (size_t)reply.ar_hln),
+                                      inet_ntoa(address));
+                               errno = EEXIST;
+                               retval = -1;
+                               goto eexit;
+                       }
                }
        }
 

diff --git a/net.h b/net.h
index d821fdbd6367926fe2eb7f50ff8e7840756409f4..77e4b6f9a65b26e555f9a7a6688d926f8bb67cc5 100644 (file)
--- a/net.h
+++ b/net.h
@@ -171,6 +171,17 @@ ssize_t send_raw_packet(const struct interface *, int,
 ssize_t get_packet(struct interface *, void *, ssize_t);
 
 #ifdef ENABLE_ARP
+/* These are really for IPV4LL */
+#define PROBE_WAIT             1
+#define PROBE_NUM              3
+#define PROBE_MIN              1
+#define PROBE_MAX              2
+#define ANNOUNCE_WAIT          2
+#define ANNOUNCE_NUM           2
+#define ANNOUNCE_INTERVAL      2
+#define MAX_CONFLICTS          10
+#define RATE_LIMIT_INTERVAL    60
+#define DEFEND_INTERVAL                10
 int arp_claim(struct interface *, struct in_addr);
 #endif
 #endif