[PATCH] libosmocore[master]: socket: Allow disabling multicast loop on socket creation

[Harald Welte]

Review at  https://gerrit.osmocom.org/3240

socket: Allow disabling multicast loop on socket creation

This introduces a new flag OSMO_SOCK_F_NO_MCAST_LOOP, which can be used
to disable the looping back of multicast packets transmitted throug this
socket to other local sockets on the machine.

As this looping-back is active by default, a single option to deviate
from the default is deemed sufficient.

Change-Id: I24a5b1ebc3f84d2d5d4734e54df50efaea26490b
---
M include/osmocom/core/socket.h
M src/socket.c
2 files changed, 18 insertions(+), 4 deletions(-)


  git pull ssh://gerrit.osmocom.org:29418/libosmocore refs/changes/40/3240/1

diff --git a/include/osmocom/core/socket.h b/include/osmocom/core/socket.h
index 6db436a..695e1d7 100644
--- a/include/osmocom/core/socket.h
+++ b/include/osmocom/core/socket.h
@@ -20,6 +20,8 @@
 #define OSMO_SOCK_F_BIND       (1 << 1)
 /*! switch socket to non-blocking mode */
 #define OSMO_SOCK_F_NONBLOCK   (1 << 2)
+/*! disable multiast loop (IP_MULTICAST_LOOP) */
+#define OSMO_SOCK_F_NO_MCAST_LOOP (1 << 3)
 
 int osmo_sock_init(uint16_t family, uint16_t type, uint8_t proto,
                   const char *host, uint16_t port, unsigned int flags);
diff --git a/src/socket.c b/src/socket.c
index 372051f..0b8c22d 100644
--- a/src/socket.c
+++ b/src/socket.c
@@ -106,7 +106,7 @@
 
 static int osmo_sock_init_tail(int fd, uint16_t type, unsigned int flags)
 {
-       int rc = 0;
+       int rc;
 
        /* Make sure to call 'listen' on a bound, connection-oriented sock */
        if ((flags & (OSMO_SOCK_F_BIND|OSMO_SOCK_F_CONNECT)) == 
OSMO_SOCK_F_BIND) {
@@ -114,13 +114,25 @@
                case SOCK_STREAM:
                case SOCK_SEQPACKET:
                        rc = listen(fd, 10);
+                       if (rc < 0) {
+                               LOGP(DLGLOBAL, LOGL_ERROR, "unable to listen on 
socket: %s\n",
+                                       strerror(errno));
+                               return rc;
+                       }
+                       break;
                }
        }
 
-       if (rc < 0)
-               LOGP(DLGLOBAL, LOGL_ERROR, "unable to listen on socket: %s\n", 
strerror(errno));
+       if (flags & OSMO_SOCK_F_NO_MCAST_LOOP) {
+               rc = osmo_sock_mcast_loop_set(fd, false);
+               if (rc < 0) {
+                       LOGP(DLGLOBAL, LOGL_ERROR, "unable to disable multicast 
loop: %s\n",
+                               strerror(errno));
+                       return rc;
+               }
+       }
 
-       return rc;
+       return 0;
 }
 
 /*! Initialize a socket (including bind and/or connect)

-- 
To view, visit https://gerrit.osmocom.org/3240
To unsubscribe, visit https://gerrit.osmocom.org/settings

Gerrit-MessageType: newchange
Gerrit-Change-Id: I24a5b1ebc3f84d2d5d4734e54df50efaea26490b
Gerrit-PatchSet: 1
Gerrit-Project: libosmocore
Gerrit-Branch: master
Gerrit-Owner: Harald Welte <lafo...@gnumonks.org>