sm-notify: Try all addresses of a multihomed host.

When sending an SM_NOTIFY to  multi-homed host, try all the addresses
in rotation.  After 4 failures on one address, try the next.

Signed-off-by: Neil Brown <neilb@suse.de>

diff --git a/utils/statd/sm-notify.c b/utils/statd/sm-notify.c
index 0eb0b09e5cdf28ca70ee7eb4030af634db594833..a94876d1b160190c819d6b7ae82d9caf800a5805 100644 (file)
--- a/utils/statd/sm-notify.c
+++ b/utils/statd/sm-notify.c
@@ -56,6 +56,7 @@ struct nsm_host {
        char *                  name;
        char *                  path;
        nsm_address             addr;
+       struct addrinfo         *ai;
        time_t                  last_used;
        time_t                  send_next;
        unsigned int            timeout;
@@ -83,7 +84,7 @@ static void           insert_host(struct nsm_host *);
 struct nsm_host *      find_host(uint32_t);
 static int             addr_get_port(nsm_address *);
 static void            addr_set_port(nsm_address *, int);
-static int             host_lookup(int, const char *, nsm_address *);
+static struct addrinfo *host_lookup(int, const char *);
 void                   nsm_log(int fac, const char *fmt, ...);
 static int             record_pid();
 static void            drop_privs(void);
@@ -225,12 +226,14 @@ notify(void)
 
        /* Bind source IP if provided on command line */
        if (opt_srcaddr) {
-               if (!host_lookup(AF_INET, opt_srcaddr, &local_addr)) {
+               struct addrinfo *ai = host_lookup(AF_INET, opt_srcaddr);
+               if (!ai) {
                        nsm_log(LOG_WARNING,
                                "Not a valid hostname or address: \"%s\"\n",
                                opt_srcaddr);
                        exit(1);
                }
+               memcpy(&local_addr, ai->ai_addr, ai->ai_addrlen);
                /* We know it's IPv4 at this point */
        }
 
@@ -322,9 +325,19 @@ notify_host(int sock, struct nsm_host *host)
        *p++ = htonl(2);
 
        /* If we retransmitted 4 times, reset the port to force
-        * a new portmap lookup (in case statd was restarted)
+        * a new portmap lookup (in case statd was restarted).
+        * We also rotate through multiple IP addresses at this
+        * point.
         */
        if (host->retries >= 4) {
+               struct addrinfo *hold = host->ai;
+               struct addrinfo **next = &host->ai;
+               *next = hold->ai_next;
+               while ( *next )
+                       next = & (*next)->ai_next;
+               *next = hold;
+               hold->ai_next = NULL;
+               memcpy(&host->addr, hold->ai_addr, hold->ai_addrlen);
                addr_set_port(&host->addr, 0);
                host->retries = 0;
        }
@@ -437,6 +450,7 @@ recv_reply(int sock)
                        free(hp->name);
                        free(hp->path);
                        free(hp);
+                       freeaddrinfo(hp->ai);
                        return;
                }
        }
@@ -502,7 +516,11 @@ get_hosts(const char *dirname)
                        host = calloc(1, sizeof(*host));
 
                snprintf(path, sizeof(path), "%s/%s", dirname, de->d_name);
-               if (!host_lookup(AF_UNSPEC, de->d_name, &host->addr)) {
+               if (stat(path, &stb) < 0)
+                       continue;
+
+               host->ai = host_lookup(AF_UNSPEC, de->d_name);
+               if (! host->ai) {
                        nsm_log(LOG_WARNING,
                                "%s doesn't seem to be a valid address, skipped",
                                de->d_name);
@@ -510,12 +528,11 @@ get_hosts(const char *dirname)
                        continue;
                }
 
-               if (stat(path, &stb) < 0)
-                       continue;
                host->last_used = stb.st_mtime;
                host->timeout = NSM_TIMEOUT;
                host->path = strdup(path);
                host->name = strdup(de->d_name);
+               host->retries = 100; /* force address retry */
 
                insert_host(host);
                host = NULL;
@@ -658,25 +675,19 @@ addr_set_port(nsm_address *addr, int port)
        }
 }
 
-static int
-host_lookup(int af, const char *name, nsm_address *addr)
+static struct addrinfo *
+host_lookup(int af, const char *name)
 {
        struct addrinfo hints, *ai;
-       int okay = 0;
 
        memset(&hints, 0, sizeof(hints));
        hints.ai_family = af;
+       hints.ai_protocol = IPPROTO_UDP;
 
        if (getaddrinfo(name, NULL, &hints, &ai) != 0)
-               return 0;
-
-       if (ai->ai_addrlen < sizeof(*addr)) {
-               memcpy(addr, ai->ai_addr, ai->ai_addrlen);
-               okay = 1;
-       }
+               return NULL;
 
-       freeaddrinfo(ai);
-       return okay;
+       return ai;
 }
 
 /*