Merge pull request #3 from westermo/send-proxy-queries

Send proxy queries in proxy mode

README.md

@@ -57,10 +57,9 @@ Description:
     however strongly recommended to leave this setting commented out!
 
 > **Note:** the daemon needs an address on interfaces to operate, it is
-> expected that querierd runs on top of a bridge, and that the bridge
-> takes care of per-VLAN proxy queries.  Also, currently the daemon does
-> not react automatically to IP address changes, so it needs to be
-> SIGHUP'ed to use any new interface or address.
+> expected that querierd runs on top of a bridge. Also, currently the
+> daemon does not react automatically to IP address changes, so it needs
+> to be SIGHUP'ed to use any new interface or address.
 
 
 Motivation

src/config.c

@@ -76,6 +76,31 @@ struct ifi *config_find_iface(int ifindex)
     return NULL;
 }
 
+static int getmac(const char *ifname, uint8_t *mac, size_t size)
+{
+    struct ifreq ifr;
+    int rc = 0;
+    int sock;
+
+    if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
+        return 1;
+
+    ifr.ifr_addr.sa_family = AF_INET;
+    strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
+
+    if (ioctl(sock, SIOCGIFHWADDR, &ifr) == -1) {
+        rc = 1;
+        goto done;
+    }
+
+    memcpy(mac, ifr.ifr_hwaddr.sa_data, size);
+
+done:
+    close(sock);
+
+    return rc;
+}
+
 /*
  * Called by parser to add an interface to start or watch for in the future
  */
@@ -106,6 +131,9 @@ struct ifi *config_iface_add(char *ifname)
     else
 	ifi->ifi_flags |= IFIF_DOWN;
 
+    if (getmac(ifname, ifi->ifi_hwaddr, sizeof(ifi->ifi_hwaddr)))
+	logit(LOG_WARNING, errno, "failed finding hw address for iface %s", ifname);
+
     TAILQ_INSERT_TAIL(&ifaces, ifi, ifi_link);
 
     return ifi;

src/defs.h

@@ -82,6 +82,11 @@ extern char		s2[MAX_INET_BUF_LEN];
 extern char		s3[MAX_INET_BUF_LEN];
 extern char		s4[MAX_INET_BUF_LEN];
 
+#define IGMP_PROXY_QUERY_MAXLEN (sizeof(struct ether_header)	+ \
+                                 sizeof(struct ip)		+ \
+                                 4 +				  \
+                                 IGMP_MINLEN)
+
 /*
  * Limit on length of route data
  */
@@ -145,8 +150,9 @@ extern void             resetlogging(void *);
 extern void		igmp_init(void);
 extern void		igmp_exit(void);
 extern void		accept_igmp(int, size_t);
-extern size_t		build_igmp(uint32_t, uint32_t, int, int, uint32_t, int);
+extern size_t		build_igmp(uint8_t *, uint32_t, uint32_t, int, int, uint32_t, int);
 extern void		send_igmp(int, uint32_t, uint32_t, int, int, uint32_t, int);
+extern void		send_igmp_proxy(const struct ifi *);
 extern char *		igmp_packet_kind(uint32_t, uint32_t);
 extern int		igmp_debug_kind(uint32_t, uint32_t);
 

src/iface.c

@@ -82,20 +82,37 @@ void iface_zero(struct ifi *ifi)
     ifi->ifi_igmpv1_warn = 0;
 }
 
+static int iface_is_proxy(const struct ifi *ifi)
+{
+    return ifi->ifi_flags & IFIF_DISABLED;
+}
+
 /*
  * Restart IGMP Querier election
  *
  * Start by figuring out the best local address for the iface.  Check if
  * the current address is better (RFC), make sure an IPv4LL doesn't win.
  * Usually we want a real address if available.  0.0.0.0 is reserved for
- * proxy querys, which we cannot do on a plain UDP socket, and they must
- * never win an election.  (Proxy queries should be sent by the bridge.)
+ * proxy querys, which we resort to if proxy mode is active and no real
+ * querier has been seen.
  */
 void iface_check_election(struct ifi *ifi)
 {
     in_addr_t curr = 0;
     struct phaddr *pa;
 
+    if (iface_is_proxy(ifi)) {
+        if (ifi->ifi_querier && ifi->ifi_querier->al_addr)
+            return;
+
+        if (ifi->ifi_querier) {
+            pev_timer_del(ifi->ifi_querier->al_timerid);
+            free(ifi->ifi_querier);
+            ifi->ifi_querier = NULL;
+        }
+        goto elected;
+    }
+
     TAILQ_FOREACH(pa, &ifi->ifi_addrs, pa_link) {
 	in_addr_t cand = pa->pa_addr;
 
@@ -142,7 +159,8 @@ void iface_check_election(struct ifi *ifi)
      * the first query.
      */
     ifi->ifi_flags |= IFIF_QUERIER;
-    logit(LOG_DEBUG, 0, "Assuming querier duties on interface %s", ifi->ifi_name);
+    logit(LOG_DEBUG, 0, "Assuming %squerier duties on interface %s",
+          iface_is_proxy(ifi) ? "proxy " : "", ifi->ifi_name);
     send_query(ifi, allhosts_group, igmp_response_interval * IGMP_TIMER_SCALE, 0);
 }
 
@@ -269,19 +287,6 @@ static void send_query(struct ifi *ifi, uint32_t dst, int code, uint32_t group)
 {
     int datalen = 4;
 
-    if (!ifi->ifi_curr_addr) {
-	/*
-	 * If we send with source address 0.0.0.0 on a UDP socket the
-	 * kernel will go dumpster diving to find a "suitable" address
-	 * from another interface.  Obviously we don't want that ... we
-	 * would've liked to be able to send a proxy query, but that's
-	 * not possible unless SOCK_RAW, so we delegate the proxy query
-	 * mechanism to the bridge and bail out here.
-	 */
-//	logit(LOG_DEBUG, 0, "Skipping send of query on %s, no address yet.", ifi->ifi_name);
-	return;
-    }
-
     /*
      * IGMP version to send depends on the compatibility mode of the
      * interface:
@@ -297,13 +302,16 @@ static void send_query(struct ifi *ifi, uint32_t dst, int code, uint32_t group)
 	code = 0;
     }
 
-    logit(LOG_DEBUG, 0, "Sending %squery on %s",
+    logit(LOG_DEBUG, 0, "Sending %squery on %s src %s",
 	  (ifi->ifi_flags & IFIF_IGMPV1) ? "v1 " :
 	  (ifi->ifi_flags & IFIF_IGMPV2) ? "v2 " : "v3 ",
-	  ifi->ifi_name);
+	  ifi->ifi_name, inet_name(ifi->ifi_curr_addr, 1));
 
-    send_igmp(ifi->ifi_ifindex, ifi->ifi_curr_addr, dst, IGMP_MEMBERSHIP_QUERY,
-	      code, group, datalen);
+    if (ifi->ifi_curr_addr)
+        send_igmp(ifi->ifi_ifindex, ifi->ifi_curr_addr, dst, IGMP_MEMBERSHIP_QUERY,
+                  code, group, datalen);
+    else
+        send_igmp_proxy(ifi);
 }
 
 static void start_iface(struct ifi *ifi)
@@ -328,8 +336,7 @@ static void start_iface(struct ifi *ifi)
     /*
      * Check if we should assume the querier role
      */
-    if (!(ifi->ifi_flags & IFIF_DISABLED))
-	iface_check_election(ifi);
+    iface_check_election(ifi);
 
     logit(LOG_INFO, 0, "Interface %s now in service", ifi->ifi_name);
 }
@@ -382,7 +389,7 @@ static void query_groups(int period, void *arg)
 {
     struct ifi *ifi = (struct ifi *)arg;
 
-    if (ifi->ifi_flags & (IFIF_DOWN | IFIF_DISABLED))
+    if (ifi->ifi_flags & IFIF_DOWN)
 	return;
 
     if (ifi->ifi_flags & IFIF_QUERIER)

src/iface.h

@@ -22,6 +22,7 @@ struct ifi {
     struct listaddr *ifi_querier;        /* IGMP querier (one or none)        */
     int		     ifi_timerid;	 /* IGMP query timer           	      */
     int		     ifi_igmpv1_warn;    /* To rate-limit IGMPv1 warnings     */
+    uint8_t	     ifi_hwaddr[6];	 /* MAC address of this interface     */
 };
 
 #define IFIF_DOWN		0x000100 /* kernel state of interface */