New configuration option LWIP_IGMP to enable IGMP processing. Based on only one filter per all network interfaces. Declare a new function in netif to enable to control the MAC filter (to reduce lwIP traffic processing).

Mace Gael for the upper layers, Steve Reynolds for lower ones...

src/api/api_lib.c

@@ -682,6 +682,37 @@ netconn_close(struct netconn *conn)
   return conn->err;
 }
 
+#if LWIP_IGMP
+err_t
+netconn_join_leave_group (struct netconn *conn,
+                          struct ip_addr *multiaddr,
+                          struct ip_addr *interface,
+                          u16_t join_or_leave)
+{
+  struct api_msg msg;
+  struct ip_addr *ipaddr[2];
+
+  if (conn == NULL) {
+    return ERR_VAL;
+  }
+
+  if (conn->err != ERR_OK) {
+    return conn->err;
+  }
+
+  msg.type = API_MSG_JOIN_LEAVE;
+  msg.msg.conn = conn;
+  ipaddr[0] = multiaddr;
+  ipaddr[1] = interface;
+  msg.msg.msg.bc.ipaddr = (struct ip_addr *)ipaddr;
+  msg.msg.msg.bc.port = join_or_leave;
+  api_msg_post(&msg);
+  
+  sys_mbox_fetch(conn->mbox, NULL);
+  return conn->err;
+}
+#endif /* LWIP_IGMP */
+
 err_t
 netconn_err(struct netconn *conn)
 {

src/api/api_msg.c

@@ -36,6 +36,7 @@
 #include "lwip/memp.h"
 #include "lwip/sys.h"
 #include "lwip/tcpip.h"
+#include "lwip/igmp.h"
 
 #if LWIP_RAW
 static u8_t
@@ -788,6 +789,41 @@ do_close(struct api_msg_msg *msg)
   }
   sys_mbox_post(msg->conn->mbox, NULL);
 }
+ 
+#if LWIP_IGMP
+static void
+do_join_leave_group(struct api_msg_msg *msg)
+{
+  err_t err = ERR_OK;
+  
+  if (msg->conn->pcb.tcp != NULL) {
+    switch (msg->conn->type) {
+#if LWIP_RAW
+    case NETCONN_RAW:
+      break;
+#endif
+#if LWIP_UDP
+    case NETCONN_UDPLITE:
+    case NETCONN_UDPNOCHKSUM:
+    case NETCONN_UDP:
+      switch(msg->msg.bc.port){
+        case NETCONN_JOIN:  err = igmp_joingroup (netif_default, ((struct ip_addr**)(msg->msg.bc.ipaddr))[0]); break;
+        case NETCONN_LEAVE: err = igmp_leavegroup(netif_default, ((struct ip_addr**)(msg->msg.bc.ipaddr))[0]); break;
+      }
+      break;
+#endif /* LWIP_UDP */
+#if LWIP_TCP
+    case NETCONN_TCP:
+        break;
+#endif
+    default:      
+      break;
+    }
+  }
+  msg->conn->err = err;      
+  sys_mbox_post(msg->conn->mbox, NULL);
+}
+#endif /* LWIP_IGMP */
 
 typedef void (* api_msg_decode)(struct api_msg_msg *msg);
 static api_msg_decode decode[API_MSG_MAX] = {
@@ -801,7 +837,10 @@ static api_msg_decode decode[API_MSG_MAX] = {
   do_send,
   do_recv,
   do_write,
-  do_close
+  do_close,
+#if LWIP_IGMP
+  do_join_leave_group
+#endif /* LWIP_IGMP */
   };
 void
 api_msg_input(struct api_msg *msg)

src/api/sockets.c

@@ -39,7 +39,7 @@
 #include "lwip/api.h"
 #include "lwip/arch.h"
 #include "lwip/sys.h"
-
+#include "lwip/igmp.h"
 #include "lwip/sockets.h"
 
 #define NUM_SOCKETS MEMP_NUM_NETCONN
@@ -1237,6 +1237,21 @@ int lwip_setsockopt (int s, int level, int optname, const void *optval, socklen_
         err = EINVAL;
       }
         break;
+    #if LWIP_IGMP
+    case IP_MULTICAST_TTL:
+     { if(( optlen != sizeof(char) ) && ( optlen != sizeof(int) )) //NOTE, some BSD implementation use "int", some others "char"
+        { err = EINVAL;
+        }
+       break;
+     }
+    case IP_ADD_MEMBERSHIP:
+    case IP_DROP_MEMBERSHIP:
+      { if( optlen < sizeof(struct ip_mreq) )
+         { err = EINVAL;
+         }
+        break;
+      }
+    #endif /* LWIP_IGMP */
       default:
       LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_IP, UNIMPL: optname=0x%x, ..)\n", s, optname));
       err = ENOPROTOOPT;
@@ -1328,6 +1343,27 @@ int lwip_setsockopt (int s, int level, int optname, const void *optval, socklen_
       sock->conn->pcb.tcp->tos = (u8_t)(*(int*)optval);
       LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_IP, IP_TOS, ..)-> %u\n", s, sock->conn->pcb.tcp->tos));
       break;
+    #if LWIP_IGMP
+    case IP_MULTICAST_TTL:
+     { if (optlen==sizeof(int))  sock->conn->pcb.tcp->ttl = (u8_t)(*(int*) optval);
+       if (optlen==sizeof(u8_t)) sock->conn->pcb.tcp->ttl = (u8_t)(*(u8_t*)optval);
+       break;
+     }
+    case IP_ADD_MEMBERSHIP:
+    case IP_DROP_MEMBERSHIP:
+     { /* If this is a TCP or a RAW socket, ignore these options. */
+       if ((sock->conn->type == NETCONN_TCP) || (sock->conn->type == NETCONN_RAW))
+        { err = EAFNOSUPPORT;
+        }
+       else
+        { struct ip_mreq *imr = (struct ip_mreq *)optval;
+          if (netconn_join_leave_group( sock->conn, (struct ip_addr *)&(imr->imr_multiaddr.s_addr), (struct ip_addr *)&(imr->imr_interface.s_addr), ((optname==IP_ADD_MEMBERSHIP)?NETCONN_JOIN:NETCONN_LEAVE)) < 0)
+           { err = EADDRNOTAVAIL;
+           }
+        }
+       break;
+     }
+    #endif /* LWIP_IGMP */
     }  /* switch */
     break;
 

src/api/tcpip.c

@@ -45,6 +45,7 @@
 #include "lwip/tcp.h"
 
 #include "lwip/tcpip.h"
+#include "lwip/igmp.h"
 
 static void (* tcpip_init_done)(void *arg) = NULL;
 static void *tcpip_init_done_arg;
@@ -168,6 +169,9 @@ tcpip_thread(void *arg)
   sys_timeout(DHCP_COARSE_TIMER_SECS*1000, dhcp_timer_coarse, NULL);
   sys_timeout(DHCP_FINE_TIMER_MSECS, dhcp_timer_fine, NULL);
 #endif
+#if LWIP_IGMP
+  igmp_init();
+#endif
 
   if (tcpip_init_done != NULL) {
     tcpip_init_done(tcpip_init_done_arg);