udp: Log transmission and reception errors, at least some of the time

We keep a bitmask for each combination of
  - receive/send
  - address family
  - success/failure
and log a message the first time each one occurs.

We also provide a new utility function `af_name()' which is going to
be used by polypath's logging.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/comm-common.h b/comm-common.h
index a9445e0fa71f0eb3d0d0cad94f09c931850e7f7c..5ab6e467f4ed2c5ed105404dc6193d0e742119a4 100644 (file)
--- a/comm-common.h
+++ b/comm-common.h
@@ -53,9 +53,12 @@ void comm_apply(struct commcommon *cc);
 
 #define UDP_MAX_SOCKETS 3 /* 2 ought to do really */
 
+#define MAX_AF (AF_INET6>AF_INET?AF_INET6:AF_INET)
+
 struct udpsock {
     union iaddr addr;
     int fd;
+    bool_t experienced[/*0=recv,1=send*/2][MAX_AF+1][/*success?*/2];
 };
 
 struct udpsocks {
@@ -81,6 +84,12 @@ bool_t udp_make_socket(struct udpcommon *uc, struct udpsock *us,
 void udp_destroy_socket(struct udpcommon *uc, struct udpsock *us);
   /* Idempotent.  No errors are possible. */
 
+const char *af_name(int af);
+void udp_sock_experienced(struct log_if *lg, struct udpcommon *uc,
+                         const char *socksdesc, struct udpsock *us,
+                         bool_t recvsend, int af /* 0 means any */,
+                         int r, int errnoval);
+
 void udp_socks_register(struct udpcommon *uc, struct udpsocks *socks);
 void udp_socks_deregister(struct udpcommon *uc, struct udpsocks *socks);
 

diff --git a/udp.c b/udp.c
index 352756cdfe417b498fc6186ba66972c613335197..364a394d25c4ab01b5e112288c93ba853dcbc56a 100644 (file)
--- a/udp.c
+++ b/udp.c
@@ -60,6 +60,34 @@ static int udp_socks_beforepoll(void *state, struct pollfd *fds, int *nfds_io,
     return 0;
 }
 
+const char *af_name(int af)
+{
+    switch (af) {
+    case AF_INET6: return "IPv6";
+    case AF_INET:  return "IPv4";
+    case 0:        return "(any)";
+    default: abort();
+    }
+}
+
+void udp_sock_experienced(struct log_if *lg, struct udpcommon *uc,
+                         const char *socksdesc, struct udpsock *us,
+                         bool_t recvsend, int af,
+                         int r, int errnoval)
+{
+    bool_t success=r>=0;
+    if (us->experienced[recvsend][af][success]++)
+       return;
+    lg_perror(lg, uc->cc.cl.description, &uc->cc.loc,
+             success ? M_INFO : M_WARNING,
+             success ? 0 : errnoval,
+             "%s [%s] experiencing some %s %s%s%s",
+             socksdesc,iaddr_to_string(&us->addr),
+             success?"success":"trouble",
+             recvsend?"transmitting":"receiving",
+             af?" ":"", af?af_name(af):"");
+}
+
 static void udp_socks_afterpoll(void *state, struct pollfd *fds, int nfds)
 {
     struct udpsocks *socks=state;
@@ -127,6 +155,8 @@ static void udp_socks_afterpoll(void *state, struct pollfd *fds, int nfds)
                }
                BUF_ASSERT_FREE(cc->rbuf);
            } else { /* rv<=0 */
+               if (errno!=EINTR && !iswouldblock(errno))
+                   udp_sock_experienced(0,uc, "socket",us, 0,0, rv,errno);
                BUF_FREE(cc->rbuf);
            }
        } while (rv>=0);
@@ -153,8 +183,10 @@ static bool_t udp_sendmsg(void *commst, struct buffer_if *buf,
        memcpy(sa,&dest->ia.sin.sin_addr,4);
        memset(sa+4,0,4);
        memcpy(sa+6,&dest->ia.sin.sin_port,2);
-       sendto(us->fd,sa,buf->size+8,0,(struct sockaddr *)&uc->proxy,
-              sizeof(uc->proxy));
+       int r=sendto(us->fd,sa,buf->size+8,0,
+                    (struct sockaddr *)&uc->proxy,
+                    sizeof(uc->proxy));
+       udp_sock_experienced(0,uc, "proxy",us, 1,0, r,errno);
        buf_unprepend(buf,8);
     } else {
        int i,r;
@@ -167,6 +199,7 @@ static bool_t udp_sendmsg(void *commst, struct buffer_if *buf,
                continue;
            r=sendto(us->fd, buf->start, buf->size, 0,
                     &dest->ia.sa, iaddr_socklen(&dest->ia));
+           udp_sock_experienced(0,uc, "socket",us, 1,af, r,errno);
            if (!r) return True;
            if (!(errno==EAFNOSUPPORT || errno==ENETUNREACH))
                /* who knows what that error means? */
@@ -199,6 +232,7 @@ bool_t udp_make_socket(struct udpcommon *uc, struct udpsock *us,
        goto failed;                                            \
     }while(0)
 
+    FILLZERO(us->experienced);
     us->fd=socket(addr->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
     if (us->fd<0) FAIL("socket");
     setnonblock(us->fd);