MINOR: sock: add a function to check for SO_REUSEPORT support at runtime
The new function _sock_supports_reuseport() will be used to check if a
protocol type supports SO_REUSEPORT or not. This will be useful to verify
that shards can really work.
diff --git a/include/haproxy/sock.h b/include/haproxy/sock.h
index 49dffa9..60e81ec 100644
--- a/include/haproxy/sock.h
+++ b/include/haproxy/sock.h
@@ -49,6 +49,7 @@
int sock_drain(struct connection *conn);
int sock_check_events(struct connection *conn, int event_type);
void sock_ignore_events(struct connection *conn, int event_type);
+int _sock_supports_reuseport(const struct proto_fam *fam, int type, int protocol);
#endif /* _HAPROXY_SOCK_H */
diff --git a/src/sock.c b/src/sock.c
index 3bc92fb..fd92783 100644
--- a/src/sock.c
+++ b/src/sock.c
@@ -995,6 +995,65 @@
fd_stop_send(conn->handle.fd);
}
+/* Live check to see if a socket type supports SO_REUSEPORT for the specified
+ * family and socket() settings. Returns non-zero on success, 0 on failure. Use
+ * protocol_supports_flag() instead, which checks cached flags.
+ */
+int _sock_supports_reuseport(const struct proto_fam *fam, int type, int protocol)
+{
+ int ret = 0;
+#ifdef SO_REUSEPORT
+ struct sockaddr_storage ss;
+ socklen_t sl = sizeof(ss);
+ int fd1, fd2;
+
+ /* for the check, we'll need two sockets */
+ fd1 = fd2 = -1;
+
+ /* ignore custom sockets */
+ if (!fam || fam->sock_domain >= AF_MAX)
+ goto leave;
+
+ fd1 = socket(fam->sock_domain, type, protocol);
+ if (fd1 < 0)
+ goto leave;
+
+ if (setsockopt(fd1, SOL_SOCKET, SO_REUSEPORT, &one, sizeof(one)) < 0)
+ goto leave;
+
+ /* bind to any address assigned by the kernel, we'll then try to do it twice */
+ memset(&ss, 0, sizeof(ss));
+ ss.ss_family = fam->sock_family;
+ if (bind(fd1, (struct sockaddr *)&ss, fam->sock_addrlen) < 0)
+ goto leave;
+
+ if (getsockname(fd1, (struct sockaddr *)&ss, &sl) < 0)
+ goto leave;
+
+ fd2 = socket(fam->sock_domain, type, protocol);
+ if (fd2 < 0)
+ goto leave;
+
+ if (setsockopt(fd2, SOL_SOCKET, SO_REUSEPORT, &one, sizeof(one)) < 0)
+ goto leave;
+
+ if (bind(fd2, (struct sockaddr *)&ss, sl) < 0)
+ goto leave;
+
+ /* OK we could bind twice to the same address:port, REUSEPORT
+ * is supported for this protocol.
+ */
+ ret = 1;
+
+ leave:
+ if (fd2 >= 0)
+ close(fd2);
+ if (fd1 >= 0)
+ close(fd1);
+#endif
+ return ret;
+}
+
/*
* Local variables:
* c-indent-level: 8