PingClient: Copy timestamp of icmp data field (seL4#45)

Copy the timestamp inside the icmp data field
in order to allow for correct display of rtt.
All data included in the icmp echo request
must be included in the icmp echo reply.

Signed-off-by: Felix Schladt <[email protected]>

apps/Arm/vm_virtio_net/components/PingClient/ping_client.c

@@ -133,12 +133,13 @@ int create_icmp_req_reply(char *recv_data, unsigned int recv_data_size)
     struct ethhdr *eth_req = (struct ethhdr *) recv_data;
     struct iphdr *ip_req = (struct iphdr *)(recv_data + sizeof(struct ethhdr));
     struct icmphdr *icmp_req = (struct icmphdr *)(recv_data + sizeof(struct ethhdr) + sizeof(struct iphdr));
+    char *icmp_msg_req = (char *)(icmp_req + 1);
 
     char reply_buffer[ETHERMTU];
     struct ethhdr *eth_reply = (struct ethhdr *) reply_buffer;
     struct iphdr *ip_reply = (struct iphdr *)(reply_buffer + sizeof(struct ethhdr));
     struct icmphdr *icmp_reply = (struct icmphdr *)(reply_buffer + sizeof(struct ethhdr) + sizeof(struct iphdr));
-    char *icmp_msg = (char *)(icmp_reply + 1);
+    char *icmp_reply_msg = (char *)(icmp_reply + 1);
 
     memcpy(eth_reply->h_dest, eth_req->h_source, ETH_ALEN);
     memcpy(eth_reply->h_source, eth_req->h_dest, ETH_ALEN);
@@ -149,10 +150,13 @@ int create_icmp_req_reply(char *recv_data, unsigned int recv_data_size)
     ip_reply->saddr = ip_reply->daddr;
     ip_reply->daddr = saddr;
 
-    memset(icmp_msg, 0, ICMP_MSG_SIZE);
     icmp_reply->un.echo.sequence =  icmp_req->un.echo.sequence;
     icmp_reply->un.echo.id = icmp_req->un.echo.id;
     icmp_reply->type = ICMP_ECHOREPLY;
+    /* Copy data (timestamp + dummy data) from request */
+    memcpy(icmp_reply_msg, icmp_msg_req, ICMP_MSG_SIZE);
+    /* Need to set checksum to 0 before calculating checksum */
+    icmp_reply->checksum = 0;
     icmp_reply->checksum = one_comp_checksum((char *)icmp_reply, sizeof(struct icmphdr) + ICMP_MSG_SIZE);
 
     /* Need to set checksum to 0 before calculating checksum of the header */