Added commandline option '-r' to set the per-socket receive buffer size.

diff --git a/candump.c b/candump.c
index 9300e7dc942a8c8e0fb34c15b9e1bf11a974ec6d..ae203747fd126d024dcceb11cc6b865ec462eb85 100644 (file)
--- a/candump.c
+++ b/candump.c
@@ -115,6 +115,7 @@ void print_usage(char *prg)
        fprintf(stderr, "         -l          (log CAN-frames into file. Sets '-s %d' by default)\n", SILENT_ON);
        fprintf(stderr, "         -L          (use log file format on stdout)\n");
        fprintf(stderr, "         -n <count>  (terminate after receiption of <count> CAN frames)\n");
+       fprintf(stderr, "         -r <size>   (set socket receive buffer to <size>)\n");
        fprintf(stderr, "\n");
        fprintf(stderr, "Up to %d CAN interfaces with optional filter sets can be specified\n", MAXSOCK);
        fprintf(stderr, "on the commandline in the form: <ifname>[,filter]*\n");
@@ -203,6 +204,7 @@ int main(int argc, char **argv)
        unsigned char log = 0;
        unsigned char logfrmt = 0;
        int count = 0;
+       int rcvbuf_size = 0;
        int opt, ret;
        int currmax, numfilter;
        char *ptr, *nptr;
@@ -222,7 +224,7 @@ int main(int argc, char **argv)
        last_tv.tv_sec  = 0;
        last_tv.tv_usec = 0;
 
-       while ((opt = getopt(argc, argv, "t:ciaSs:b:B:lLn:h?")) != -1) {
+       while ((opt = getopt(argc, argv, "t:ciaSs:b:B:lLn:r:h?")) != -1) {
                switch (opt) {
                case 't':
                        timestamp = optarg[0];
@@ -313,6 +315,14 @@ int main(int argc, char **argv)
                        }
                        break;
 
+               case 'r':
+                       rcvbuf_size = atoi(optarg);
+                       if (rcvbuf_size < 1) {
+                               print_usage(basename(argv[0]));
+                               exit(1);
+                       }
+                       break;
+
                default:
                        print_usage(basename(argv[0]));
                        exit(1);
@@ -452,6 +462,30 @@ int main(int argc, char **argv)
 
                } /* if (nptr) */
 
+               if (rcvbuf_size) {
+
+                       int curr_rcvbuf_size;
+                       socklen_t curr_rcvbuf_size_len = sizeof(curr_rcvbuf_size);
+
+                       if (setsockopt(s[i], SOL_SOCKET, SO_RCVBUF,
+                                      &rcvbuf_size, sizeof(rcvbuf_size)) < 0) {
+                               perror("setsockopt SO_RCVBUF");
+                               exit(1);
+                       }
+
+                       if (getsockopt(s[i], SOL_SOCKET, SO_RCVBUF,
+                                      &curr_rcvbuf_size, &curr_rcvbuf_size_len) < 0) {
+                               perror("getsockopt SO_RCVBUF");
+                               exit(1);
+                       }
+
+                       /* Only print a warning the first time we detect the adjustment */
+                       /* n.b.: The wanted size is doubled in Linux in net/sore/sock.c */
+                       if (!i && curr_rcvbuf_size < rcvbuf_size*2)
+                               fprintf(stderr, "The socket receive buffer size was "
+                                       "adjusted due to /proc/sys/net/core/rmem_max.\n");
+               }
+
                if (bind(s[i], (struct sockaddr *)&addr, sizeof(addr)) < 0) {
                        perror("bind");
                        return 1;