[GitHub] [nuttx] anchao commented on a diff in pull request #7616: net/l2/l3/l4: add support of iob offload

[GitBox]

anchao commented on code in PR #7616:
URL: https://github.com/apache/nuttx/pull/7616#discussion_r1037778614


##########
net/icmp/icmp_reply.c:
##########
@@ -119,20 +119,75 @@ void icmp_reply(FAR struct net_driver_s *dev, int type, 
int code)
   if (datalen > ICMP_MAXMSGLEN - ipicmplen)
     {
       datalen = ICMP_MAXMSGLEN - ipicmplen;
+      iob_trimtail(dev->d_iob, dev->d_iob->io_pktlen - datalen);
     }
 
-  dev->d_len = ipicmplen + datalen;
+  /* Save the original datagram */
+
+  if (CONFIG_IOB_BUFSIZE >= datalen + ipicmplen +
+                           CONFIG_NET_LL_GUARDSIZE)
+    {
+      /* Reuse current iob */
+
+      memmove((FAR char *)ipv4 + ipicmplen, ipv4, datalen);
+
+      /* Skip icmp header from iob */
+
+      iob_update_pktlen(dev->d_iob, datalen + ipicmplen);
+    }
+  else
+    {
+      FAR struct iob_s *iob;
+
+      /* Save the original datagram to iob chain */
+
+      iob = dev->d_iob;
+      dev->d_iob = NULL;
+
+      /* Re-prepare device buffer */
 
-  /* Copy fields from original packet */
+      if (netdev_iob_prepare(dev, false, 0) != OK)
+        {
+          dev->d_len = 0;
+          dev->d_iob = iob;
+          netdev_iob_release(dev);
+          return;
+        }
 
-  memmove(icmp + 1, ipv4, datalen);
+      /* Copy ipv4 header to device buffer */
+
+      if (iob_trycopyin(dev->d_iob, (FAR void *)ipv4,
+                        IPv4_HDRLEN, 0, false) != IPv4_HDRLEN)
+        {
+          dev->d_len = 0;
+          netdev_iob_release(dev);
+          iob_free_chain(iob);
+          return;
+        }
+
+      /* Skip icmp header from iob */
+
+      iob_update_pktlen(dev->d_iob, dev->d_iob->io_pktlen +
+                                    sizeof(struct icmp_hdr_s));
+
+      /* Concat new icmp packet before original datagram */
+
+      iob_concat(dev->d_iob, iob);
+
+      /* IPv4 header to new iob */
+
+      ipv4 = IPBUF(0);
+    }
+
+  dev->d_len = ipicmplen + datalen;
 
   ipv4_build_header(IPv4BUF, dev->d_len, IP_PROTO_ICMP,
                     &dev->d_ipaddr, (FAR in_addr_t *)ipv4->srcipaddr,
                     IP_TTL_DEFAULT, NULL);
 
   /* Initialize the ICMP header */
 
+  icmp = (FAR struct icmp_hdr_s *)(ipv4 + 1);
   icmp->type        = type;

Review Comment:
   Done



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