socket: Add support for socket protcol

Now we don't support the socket protocol like
sctp and udplite .

This patch add a new config param
SocketProtocol: udplite/sctp

With this now we can configure the protocol as

udplite = IPPROTO_UDPLITE
sctp = IPPROTO_SCTP

Tested with nspawn:

man/systemd.socket.xml

@@ -310,6 +310,15 @@
         </para></listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><varname>SocketProtocol=</varname></term>
+        <listitem><para>Takes a one of <option>udplite</option>
+        or <option>sctp</option>. Specifies a socket protocol
+        (<constant>IPPROTO_UDPLITE</constant>) UDP-Lite
+        (<constant>IPPROTO_SCTP</constant>) SCTP socket respectively. </para>
+        </listitem>
+      </varlistentry>
+
       <varlistentry>
         <term><varname>BindIPv6Only=</varname></term>
         <listitem><para>Takes a one of <option>default</option>,

src/core/load-fragment-gperf.gperf.m4

@@ -249,6 +249,7 @@ Socket.ListenNetlink,            config_parse_socket_listen,         SOCKET_SOCK
 Socket.ListenSpecial,            config_parse_socket_listen,         SOCKET_SPECIAL,                0
 Socket.ListenMessageQueue,       config_parse_socket_listen,         SOCKET_MQUEUE,                 0
 Socket.ListenUSBFunction,        config_parse_socket_listen,         SOCKET_USB_FUNCTION,           0
+Socket.SocketProtocol,           config_parse_socket_protocol,       0,                             0
 Socket.BindIPv6Only,             config_parse_socket_bind,           0,                             0,
 Socket.Backlog,                  config_parse_unsigned,              0,                             offsetof(Socket, backlog)
 Socket.BindToDevice,             config_parse_socket_bindtodevice,   0,                             0

src/core/load-fragment.c

@@ -421,6 +421,37 @@ int config_parse_socket_listen(const char *unit,
         return 0;
 }
 
+int config_parse_socket_protocol(const char *unit,
+                                 const char *filename,
+                                 unsigned line,
+                                 const char *section,
+                                 unsigned section_line,
+                                 const char *lvalue,
+                                 int ltype,
+                                 const char *rvalue,
+                                 void *data,
+                                 void *userdata) {
+        Socket *s;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        s = SOCKET(data);
+
+        if (streq(rvalue, "udplite"))
+                s->socket_protocol = IPPROTO_UDPLITE;
+        else if (streq(rvalue, "sctp"))
+                s->socket_protocol = IPPROTO_SCTP;
+        else {
+                log_syntax(unit, LOG_ERR, filename, line, 0, "Socket protocol not supported, ignoring: %s", rvalue);
+                return 0;
+        }
+
+        return 0;
+}
+
 int config_parse_socket_bind(const char *unit,
                              const char *filename,
                              unsigned line,

src/core/load-fragment.h

@@ -38,6 +38,7 @@ int config_parse_unit_path_printf(const char *unit, const char *filename, unsign
 int config_parse_unit_path_strv_printf(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_documentation(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_socket_listen(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
+int config_parse_socket_protocol(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_socket_bind(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_exec_nice(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
 int config_parse_exec_oom_score_adjust(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);

src/core/socket.c

@@ -1266,6 +1266,19 @@ static int socket_open_fds(Socket *s) {
                                 know_label = true;
                         }
 
+                        /* Apply the socket protocol */
+                        switch(p->address.type) {
+                        case SOCK_STREAM:
+                        case SOCK_SEQPACKET:
+                                if (p->socket->socket_protocol == IPPROTO_SCTP)
+                                        p->address.protocol = p->socket->socket_protocol;
+                                break;
+                        case SOCK_DGRAM:
+                                if (p->socket->socket_protocol == IPPROTO_UDPLITE)
+                                        p->address.protocol = p->socket->socket_protocol;
+                                break;
+                        }
+
                         r = socket_address_listen(
                                         &p->address,
                                         SOCK_CLOEXEC|SOCK_NONBLOCK,

src/core/socket.h

@@ -120,6 +120,8 @@ struct Socket {
         bool remove_on_stop;
         bool writable;
 
+        int socket_protocol;
+
         /* Socket options */
         bool keep_alive;
         bool no_delay;