sockets.h, sockets.c: Implement MSG_PEEK flag for recv/recvfrom functions.

CHANGELOG

@@ -19,6 +19,9 @@ HISTORY
 
   ++ New features:
 
+  2007-06-30 Frédéric Bernon
+  * sockets.h, sockets.c: Implement MSG_PEEK flag for recv/recvfrom functions.
+
   2007-06-21 Simon Goldschmidt
   * etharp.h, etharp.c: Combined etharp_request with etharp_raw for both
     LWIP_AUTOIP =0 and =1 to remove redundant code.

src/api/sockets.c

@@ -381,7 +381,6 @@ lwip_recvfrom(int s, void *mem, int len, unsigned int flags,
   struct ip_addr     *addr;
   u16_t               port;
 
-
   LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom(%d, %p, %d, 0x%x, ..)\n", s, mem, len, flags));
   sock = get_socket(s);
   if (!sock)
@@ -397,11 +396,11 @@ lwip_recvfrom(int s, void *mem, int len, unsigned int flags,
       sock_set_errno(sock, EWOULDBLOCK);
       return -1;
     }
-     
+
     /* No data was left from the previous operation, so we try to get
     some from the network. */
-    buf = netconn_recv(sock->conn);
-    
+    sock->lastdata = buf = netconn_recv(sock->conn);
+
     if (!buf) {
       /* We should really do some error checking here. */
       LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom(%d): buf == NULL!\n", s));
@@ -413,13 +412,13 @@ lwip_recvfrom(int s, void *mem, int len, unsigned int flags,
   buflen = netbuf_len(buf);
 
   buflen -= sock->lastoffset;
-  
+
   if (len > buflen) {
     copylen = buflen;
   } else {
     copylen = len;
   }
-  
+
   /* copy the contents of the received buffer into
   the supplied memory pointer mem */
   netbuf_copy_partial(buf, mem, copylen, sock->lastoffset);
@@ -454,19 +453,21 @@ lwip_recvfrom(int s, void *mem, int len, unsigned int flags,
     ip_addr_debug_print(SOCKETS_DEBUG, addr);
     LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%u len=%u\n", port, copylen));
 #endif
-
   }
 
-  /* If this is a TCP socket, check if there is data left in the
-     buffer. If so, it should be saved in the sock structure for next
-     time around. */
-  if ((sock->conn->type == NETCONN_TCP) && (buflen - copylen > 0)) {
-    sock->lastdata = buf;
-    sock->lastoffset += copylen;
-  } else {
-    sock->lastdata = NULL;
-    sock->lastoffset = 0;
-    netbuf_delete(buf);
+  /* If we don't peek the incoming message... */
+  if ((flags & MSG_PEEK)==0) {
+    /* If this is a TCP socket, check if there is data left in the
+       buffer. If so, it should be saved in the sock structure for next
+       time around. */
+    if ((sock->conn->type == NETCONN_TCP) && (buflen - copylen > 0)) {
+      sock->lastdata = buf;
+      sock->lastoffset += copylen;
+    } else {
+      sock->lastdata = NULL;
+      sock->lastoffset = 0;
+      netbuf_delete(buf);
+    }
   }
 
   sock_set_errno(sock, 0);

src/include/lwip/sockets.h

@@ -121,11 +121,14 @@ struct linger {
 #define IPPROTO_UDP     17
 #define IPPROTO_UDPLITE 136
 
-#define INADDR_ANY      0
+#define INADDR_ANY       0
 #define INADDR_BROADCAST 0xffffffff
 
 /* Flags we can use with send and recv. */
-#define MSG_DONTWAIT    0x40            /* Nonblocking i/o for this operation only */
+#define MSG_PEEK       0x01    /* Peeks at an incoming message */
+#define MSG_WAITALL    0x02    /* Requests that the function block until the full amount of data requested can be returned */
+#define MSG_OOB        0x04    /* Requests out-of-band data. The significance and semantics of out-of-band data are protocol-specific */
+#define MSG_DONTWAIT   0x08    /* Nonblocking i/o for this operation only */
 
 
 /*
@@ -140,7 +143,7 @@ struct linger {
  */
 #define TCP_NODELAY    0x01    /* don't delay send to coalesce packets */
 #define TCP_KEEPALIVE  0x02    /* send KEEPALIVE probes when idle for pcb->keep_idle milliseconds */
-#define TCP_KEEPIDLE   0x03    /* set pcb->keep_idle  - Same as TCP_KEEPALIVE, but use seconds for get/setsockopt*/
+#define TCP_KEEPIDLE   0x03    /* set pcb->keep_idle  - Same as TCP_KEEPALIVE, but use seconds for get/setsockopt */
 #define TCP_KEEPINTVL  0x04    /* set pcb->keep_intvl - Use seconds for get/setsockopt */
 #define TCP_KEEPCNT    0x05    /* set pcb->keep_cnt   - Use number of probes sent for get/setsockopt */
 #endif /* LWIP_TCP */