Changes from Patch #1871 (more Raw IP functionality)

src/core/raw.c

@@ -72,13 +72,14 @@ raw_init(void)
  * Determine if in incoming IP packet is covered by a RAW pcb and
  * and process it if possible
  *
- * Given an incoming UDP datagram (as a chain of pbufs) this function
- * finds a corresponding UDP PCB and
+ * Given an incoming IP datagram (as a chain of pbufs) this function
+ * finds a corresponding RAW PCB and
  *
- * @param pbuf pbuf to be demultiplexed to a UDP PCB.
+ * @param pbuf pbuf to be demultiplexed to a RAW PCB.
  * @param netif network interface on which the datagram was received.
- * @return 0 if packet cannot be handled (pbuf needs to be freed then)
- *         or 1 if the packet has been processed
+ * @return 0 if packet is not eated (pbuf needs to be freed then)
+ *         or 1 if the packet has been eaten (pbuf needs not to be freed
+ *         then)
  *
  */
 int
@@ -95,7 +96,8 @@ raw_input(struct pbuf *p, struct netif *inp)
   for(pcb = raw_pcbs; pcb != NULL; pcb = pcb->next) {
     if (pcb->protocol == proto) {
       if (pcb->recv) {
-        pcb->recv(pcb->recv_arg, pcb, p, &(iphdr->src));
+        if (!pcb->recv(pcb->recv_arg, pcb, p, &(iphdr->src)))
+          return 0;
       }
       pbuf_free(p);
       rc = 1;
@@ -126,12 +128,38 @@ raw_bind(struct raw_pcb *pcb, struct ip_addr *ipaddr)
   return ERR_OK;
 }
 
-/*-----------------------------------------------------------------------------------*/
+/**
+ * Connect an RAW PCB. This function is required by upper layers
+ * of lwip. Using the raw api you could use raw_send_to() instead
+ *
+ * This will associate the RAW PCB with the remote address.
+ *
+ * @param pcb RAW PCB to be connected with remote address ipaddr and port.
+ * @param ipaddr remote IP address to connect with.
+ *
+ * @return lwIP error code
+ *
+ * @see raw_disconnect() and raw_send_to()
+ */
+err_t
+raw_connect(struct raw_pcb *pcb, struct ip_addr *ipaddr)
+{
+  ip_addr_set(&pcb->remote_ip, ipaddr);
+  return ERR_OK;
+}
+
+
+/**
+ * Set the callback function if a RAW packet with the pcb's protocol
+ * is received. If the callback function returns a value unequal 0
+ * the raw packet is "eaten" and not forwarded to any other raw pcb
+ * including lwip itself
+ */
 void
 raw_recv(struct raw_pcb *pcb,
-   void (* recv)(void *arg, struct raw_pcb *upcb, struct pbuf *p,
-           struct ip_addr *addr),
-   void *recv_arg)
+         int (* recv)(void *arg, struct raw_pcb *upcb, struct pbuf *p,
+                      struct ip_addr *addr),
+         void *recv_arg)
 {
   /* remember recv() callback and user data */
   pcb->recv = recv;
@@ -151,19 +179,42 @@ raw_recv(struct raw_pcb *pcb,
  *
  */
 err_t
-raw_send_payload(struct raw_pcb *pcb, struct pbuf *p, struct ip_addr *ipaddr)
+raw_send_to(struct raw_pcb *pcb, struct pbuf *p, struct ip_addr *ipaddr)
 {
   err_t err;
   struct netif *netif;
   struct ip_addr *src_ip;
-
-  LWIP_DEBUGF(UDP_DEBUG | DBG_TRACE | 3, ("raw_send_payload\n"));
-
+  struct pbuf *q; /* q will be sent down the stack */
+  
+  LWIP_DEBUGF(RAW_DEBUG | DBG_TRACE | 3, ("raw_send_to\n"));
+  
+  /* not enough space to add an IP header to first pbuf in given p chain? */
+  if (pbuf_header(p, IP_HLEN)) {
+    /* allocate header in new pbuf */
+    q = pbuf_alloc(PBUF_IP, 0, PBUF_RAM);
+    /* new header pbuf could not be allocated? */
+    if (q == NULL) {
+      LWIP_DEBUGF(RAW_DEBUG | DBG_TRACE | 2, ("raw_send_to: could not allocate header\n"));
+      return ERR_MEM;
+    }
+    /* chain header q in front of given pbuf p */
+    pbuf_chain(q, p);
+    /* { first pbuf q points to header pbuf } */
+    LWIP_DEBUGF(RAW_DEBUG, ("raw_send_to: added header pbuf %p before given pbuf %p\n", (void *)q, (void *)p));
+  }  else {
+    /* first pbuf q equals given pbuf */
+    q = p;
+    pbuf_header(q, -IP_HLEN);
+  }
+  
   if ((netif = ip_route(ipaddr)) == NULL) {
-    LWIP_DEBUGF(UDP_DEBUG | 1, ("raw_send_payload: No route to 0x%lx\n", ipaddr->addr));
+    LWIP_DEBUGF(RAW_DEBUG | 1, ("raw_send_to: No route to 0x%lx\n", ipaddr->addr));
 #ifdef RAW_STATS
-/*    ++lwip_stats.raw.rterr;*/
-#endif /* UDP_STATS */
+    /*    ++lwip_stats.raw.rterr;*/
+#endif /* RAW_STATS */
+    if (q != p) {
+      pbuf_free(q);
+    }
     return ERR_RTE;
   }
 
@@ -171,13 +222,32 @@ raw_send_payload(struct raw_pcb *pcb, struct pbuf *p, struct ip_addr *ipaddr)
     /* use outgoing network interface IP address as source address */
     src_ip = &(netif->ip_addr);
   } else {
-    /* use UDP PCB local IP address as source address */
+    /* use RAW PCB local IP address as source address */
     src_ip = &(pcb->local_ip);
   }
 
-  err = ip_output_if (p, src_ip, ipaddr, 64, pcb->tos, pcb->protocol, netif);
+  err = ip_output_if (q, src_ip, ipaddr, pcb->ttl, pcb->tos, pcb->protocol, netif);
 
-  return ERR_OK;
+  /* did we chain a header earlier? */
+  if (q != p) {
+    /* free the header */
+    pbuf_free(q);
+  }
+  return err;
+}
+
+/**
+ * Send the raw IP packet to the address given by raw_connect()
+ *
+ * @param pcb the raw pcb which to send
+ * @param p the ip payload to send
+ * @param ipaddr the destination address of the whole IP packet
+ *
+ */
+err_t
+raw_send(struct raw_pcb *pcb, struct pbuf *p)
+{
+  return raw_send_to(pcb,p,&pcb->remote_ip);
 }
 
 /**
@@ -198,7 +268,7 @@ raw_remove(struct raw_pcb *pcb)
     raw_pcbs = raw_pcbs->next;
   /* pcb not 1st in list */
   } else for(pcb2 = raw_pcbs; pcb2 != NULL; pcb2 = pcb2->next) {
-    /* find pcb in udp_pcbs list */
+    /* find pcb in raw_pcbs list */
     if (pcb2->next != NULL && pcb2->next == pcb) {
       /* remove pcb from list */
       pcb2->next = pcb->next;
@@ -229,6 +299,7 @@ raw_new(u16_t proto) {
     /* initialize PCB to all zeroes */
     memset(pcb, 0, sizeof(struct raw_pcb));
     pcb->protocol = proto;
+    pcb->ttl = RAW_TTL;
     pcb->next = raw_pcbs;
     raw_pcbs = pcb;
   }