net/icmpv4: Allow for arbitrary payload data in ICMP echo

Allow for including arbitrary data in net_icmpv4_send_echo_request()
that will be echoed verbatim by the receiver.

This allows to use ICMP echo for diagnostic use cases, e.g. by testing
packet framentation (large payload) or measuring round-trip-time.

Signed-off-by: Benjamin Valentin <[email protected]>

Author: benpicco

subsys/net/ip/icmpv4.c

@@ -129,7 +129,9 @@ static enum net_verdict icmpv4_handle_echo_request(struct net_pkt *pkt,
 int net_icmpv4_send_echo_request(struct net_if *iface,
 				 struct in_addr *dst,
 				 u16_t identifier,
-				 u16_t sequence)
+				 u16_t sequence,
+				 const void *data,
+				 size_t data_size)
 {
 	NET_PKT_DATA_ACCESS_CONTIGUOUS_DEFINE(icmpv4_access,
 					      struct net_icmpv4_echo_req);
@@ -146,7 +148,8 @@ int net_icmpv4_send_echo_request(struct net_if *iface,
 	src = &iface->config.ip.ipv4->unicast[0].address.in_addr;
 
 	pkt = net_pkt_alloc_with_buffer(iface,
-					sizeof(struct net_icmpv4_echo_req),
+					sizeof(struct net_icmpv4_echo_req)
+					+ data_size,
 					AF_INET, IPPROTO_ICMP,
 					PKT_WAIT_TIME);
 	if (!pkt) {
@@ -168,6 +171,7 @@ int net_icmpv4_send_echo_request(struct net_if *iface,
 	echo_req->sequence   = htons(sequence);
 
 	net_pkt_set_data(pkt, &icmpv4_access);
+	net_pkt_write(pkt, data, data_size);
 
 	net_pkt_cursor_init(pkt);
 

subsys/net/ip/icmpv4.h

@@ -62,13 +62,18 @@ int net_icmpv4_send_error(struct net_pkt *pkt, u8_t type, u8_t code);
  * to this Echo Request. May be zero.
  * @param sequence A sequence number to aid in matching Echo Replies
  * to this Echo Request. May be zero.
+ * @param data Arbitrary payload data that will be included in the
+ * Echo Reply verbatim. May be zero.
+ * @param data_size Size of the Payload Data in bytes. May be zero.
  *
  * @return Return 0 if the sending succeed, <0 otherwise.
  */
 int net_icmpv4_send_echo_request(struct net_if *iface,
 				 struct in_addr *dst,
 				 u16_t identifier,
-				 u16_t sequence);
+				 u16_t sequence,
+				 const void *data,
+				 size_t data_size);
 
 void net_icmpv4_register_handler(struct net_icmpv4_handler *handler);
 

subsys/net/ip/net_shell.c

@@ -2763,7 +2763,9 @@ static int ping_ipv4(const struct shell *shell, char *host)
 		net_if_ipv4_select_src_iface(&ipv4_target),
 		&ipv4_target,
 		sys_rand32_get(),
-		sys_rand32_get());
+		sys_rand32_get(),
+		NULL,
+		0);
 	if (ret) {
 		remove_ipv4_ping_handler();
 	} else {