Implemented socket options SO_NO_CHECK for UDP sockets to disable UDP checksum generation on transmit.

CHANGELOG

@@ -19,6 +19,10 @@ HISTORY
 
   ++ New features:
 
+  2007-06-17 Simon Goldschmidt
+  * sockets.c, sockets.h: Implemented socket options SO_NO_CHECK for UDP sockets
+    to disable UDP checksum generation on transmit.
+
   2007-06-13 Frédéric Bernon, Simon Goldschmidt
   * debug.h, api_msg.c: change LWIP_ERROR to use it to check errors like invalid
     pointers or parameters, and let the possibility to redefined it in cc.h. Use

src/api/sockets.c

@@ -1338,6 +1338,16 @@ int lwip_setsockopt(int s, int level, int optname, const void *optval, socklen_t
         err = EINVAL;
       }
       break;
+    case SO_NO_CHECK:
+      if (optlen < sizeof(int)) {
+        err = EINVAL;
+      }
+      if ((sock->conn->type != NETCONN_UDP) ||
+          ((sock->conn->pcb.udp->flags & UDP_FLAGS_UDPLITE) == 1)) {
+        /* this flag is only available for UDP, not for UDP lite */
+        err = EAFNOSUPPORT;
+      }
+      break;
     default:
       LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, SOL_SOCKET, UNIMPL: optname=0x%x, ..)\n",
                   s, optname));
@@ -1512,6 +1522,13 @@ static void lwip_setsockopt_internal(void *arg)
       sock->conn->recv_timeout = ( *(int*)optval );
       break;
 #endif /* LWIP_SO_RCVTIMEO */
+    case SO_NO_CHECK:
+      if (*(int*)optval) {
+        udp_setflags(sock->conn->pcb.udp, udp_flags(sock->conn->pcb.udp) | UDP_FLAGS_NOCHKSUM);
+      } else {
+        udp_setflags(sock->conn->pcb.udp, udp_flags(sock->conn->pcb.udp) & ~UDP_FLAGS_NOCHKSUM);
+      }
+      break;
     }  /* switch (optname) */
     break;
 

src/include/lwip/sockets.h

@@ -94,6 +94,7 @@ struct sockaddr {
 #define SO_ERROR     0x1007    /* get error status and clear */
 #define SO_TYPE      0x1008    /* get socket type */
 #define SO_CONTIMEO  0x1009    /* connect timeout */
+#define SO_NO_CHECK  0x100a    /* don't create UDP checksum */
 
 
 /*
@@ -150,7 +151,7 @@ struct linger {
  */
 #define UDPLITE_SEND_CSCOV 0x01 /* sender checksum coverage */
 #define UDPLITE_RECV_CSCOV 0x02 /* minimal receiver checksum coverage */
-#endif
+#endif /* LWIP_UDP && LWIP_UDPLITE*/
 
 
 #if LWIP_IGMP