If we get POLLERR when polling a socket in memory-mapped mode, do a

recv() on the socket to get the error code.

diff --git a/pcap-linux.c b/pcap-linux.c
index 29d79c4959a0b12fcdf3f67122a406880ab9ed84..8356ba54ef0d8fea6de6a8f8734bce00980fb211 100644 (file)
--- a/pcap-linux.c
+++ b/pcap-linux.c
@@ -1365,7 +1365,7 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata)
                         *
                         * XXX - we should really return
                         * PCAP_ERROR_IFACE_NOT_UP, but pcap_dispatch()
-                        * etc. aren't defined to retur that.
+                        * etc. aren't defined to return that.
                         */
                        snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
                                "The interface went down");
@@ -2934,6 +2934,7 @@ pcap_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback,
                u_char *user)
 {
        int pkts = 0;
+       char c;
 
        /* wait for frames availability.*/
        if ((handle->md.timeout >= 0) &&
@@ -2970,9 +2971,35 @@ pcap_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback,
                                        return PCAP_ERROR;
                                }
                                if (pollinfo.revents & POLLERR) {
-                                       snprintf(handle->errbuf,
-                                               PCAP_ERRBUF_SIZE, 
-                                               "Error condition on packet socket");
+                                       /*
+                                        * A recv() will give us the
+                                        * actual error code.
+                                        *
+                                        * XXX - make the socket non-blocking?
+                                        */
+                                       if (recv(handle->fd, c, sizeof c,
+                                           MSG_PEEK) != -1)
+                                               continue;       /* what, no error? */
+                                       if (errno == ENETDOWN) {
+                                               /*
+                                                * The device on which we're
+                                                * capturing went away.
+                                                *
+                                                * XXX - we should really return
+                                                * PCAP_ERROR_IFACE_NOT_UP,
+                                                * but pcap_dispatch() etc.
+                                                * aren't defined to return
+                                                * that.
+                                                */
+                                               snprintf(handle->errbuf,
+                                                       PCAP_ERRBUF_SIZE,
+                                                       "The interface went down");
+                                       } else {
+                                               snprintf(handle->errbuf,
+                                                       PCAP_ERRBUF_SIZE, 
+                                                       "Error condition on packet socket: %s",
+                                                       strerror(errno));
+                                       }
                                        return PCAP_ERROR;
                                }
                                if (pollinfo.revents & POLLNVAL) {