gnrc_icmpv6_echo: implement gnrc_icmpv6_echo_{send, req_handle}()

sys/include/net/gnrc/icmpv6/echo.h

@@ -24,7 +24,9 @@
 
 #include "byteorder.h"
 #include "net/gnrc/netif.h"
+#include "net/gnrc/netif/hdr.h"
 #include "net/ipv6/hdr.h"
+#include "net/icmpv6.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -58,6 +60,49 @@ gnrc_pktsnip_t *gnrc_icmpv6_echo_build(uint8_t type, uint16_t id, uint16_t seq,
 void gnrc_icmpv6_echo_req_handle(gnrc_netif_t *netif, ipv6_hdr_t *ipv6_hdr,
                                  icmpv6_echo_t *echo, uint16_t len);
 
+/**
+ * @brief   Send out ICMPv6 echo request
+ *
+ * @param[in] netif     The interface the echo request should be sent on.
+ * @param[in] addr      The destination address of the echo request
+ * @param[in] id        ID for the echo message in host byte-order
+ * @param[in] seq       Sequence number for the echo message in host byte-order
+ * @param[in] ttl       Hop limit of the echo request
+ * @param[in] len       Length of the payload
+ *
+ * @return  0 on success
+ * @return <0 on error
+ */
+int gnrc_icmpv6_echo_send(const gnrc_netif_t *netif, const ipv6_addr_t *addr,
+                          uint16_t id, uint16_t seq, uint8_t ttl, size_t len);
+
+/**
+ * @brief   ICMPv6 echo response callback
+ *
+ * @param[in] pkt       Packet containing the ICMPv6 response
+ * @param[in] corrupt   Offset of corrupt payload, -1 if no corruption detected
+ * @param[in] rtt_us    round-trip-time in µs (0 if this information is not available)
+ * @param[in] ctx       User supplied context
+ *
+ * @return  0 on success
+ * @return <0 on error
+ */
+typedef int (*gnrc_icmpv6_echo_rsp_handle_cb_t)(gnrc_pktsnip_t *pkt,
+                                                int corrupt, uint32_t rtt_us, void *ctx);
+/**
+ * @brief   Parse ICMPv6 echo response
+ *
+ * @param[in] pkt       Incoming ICMPv6 packet
+ * @param[in] len       Expected echo response payload length
+ * @param[in] cb        Callback function to execute
+ * @param[in] ctx       Callback function context
+ *
+ * @return  0 on success
+ * @return <0 on error
+ */
+int gnrc_icmpv6_echo_rsp_handle(gnrc_pktsnip_t *pkt, size_t len,
+                                gnrc_icmpv6_echo_rsp_handle_cb_t cb, void *ctx);
+
 #ifdef __cplusplus
 }
 #endif

sys/net/gnrc/network_layer/icmpv6/echo/gnrc_icmpv6_echo.c

@@ -35,7 +35,7 @@ gnrc_pktsnip_t *gnrc_icmpv6_echo_build(uint8_t type, uint16_t id, uint16_t seq,
         return NULL;
     }
 
-    DEBUG("icmpv6_echo: Building echo message with type=%" PRIu8 "id=%" PRIu16
+    DEBUG("icmpv6_echo: Building echo message with type=%" PRIu8 " id=%" PRIu16
           ", seq=%" PRIu16, type, id, seq);
     echo = (icmpv6_echo_t *)pkt->data;
     echo->id = byteorder_htons(id);
@@ -107,4 +107,121 @@ void gnrc_icmpv6_echo_req_handle(gnrc_netif_t *netif, ipv6_hdr_t *ipv6_hdr,
     }
 }
 
+static void _fill_payload(uint8_t *buf, size_t len, uint32_t now)
+{
+    uint8_t i = 0;
+
+    if (len >= sizeof(uint32_t)) {
+        memcpy(buf, &now, sizeof(now));
+        len -= sizeof(now);
+        buf += sizeof(now);
+    }
+
+    while (len--) {
+        *buf++ = i++;
+    }
+}
+
+static void _check_payload(const void *buf, size_t len, uint32_t now,
+                           uint32_t *triptime, int *corrupt)
+{
+    uint8_t i = 0;
+    const uint8_t *data = buf;
+
+    if (len >= sizeof(uint32_t)) {
+        *triptime = now - unaligned_get_u32(buf);
+        len  -= sizeof(uint32_t);
+        data += sizeof(uint32_t);
+    }
+
+    while (len--) {
+        if (*data++ != i++) {
+            *corrupt = data - (uint8_t *)buf - 1;
+            break;
+        }
+    }
+}
+
+int gnrc_icmpv6_echo_send(const gnrc_netif_t *netif, const ipv6_addr_t *addr,
+                          uint16_t id, uint16_t seq, uint8_t ttl, size_t len)
+{
+    int res = 0;
+    gnrc_pktsnip_t *pkt, *tmp;
+    ipv6_hdr_t *ipv6;
+    uint8_t *databuf;
+
+    pkt = gnrc_icmpv6_echo_build(ICMPV6_ECHO_REQ, id, seq, NULL, len);
+    if (pkt == NULL) {
+        DEBUG("error: packet buffer full\n");
+        return -ENOMEM;
+    }
+
+    databuf = (uint8_t *)(pkt->data) + sizeof(icmpv6_echo_t);
+    tmp = gnrc_ipv6_hdr_build(pkt, NULL, addr);
+    if (tmp == NULL) {
+        puts("error: packet buffer full");
+        goto error_exit;
+    }
+    pkt = tmp;
+    ipv6 = pkt->data;
+    /* if ttl is unset (i.e. 0) gnrc_ipv6 will select hop limit */
+    ipv6->hl = ttl;
+    if (netif != NULL) {
+        tmp = gnrc_netif_hdr_build(NULL, 0, NULL, 0);
+        if (tmp == NULL) {
+            DEBUG("error: packet buffer full");
+            res = -ENOMEM;
+            goto error_exit;
+        }
+        gnrc_netif_hdr_set_netif(tmp->data, netif);
+        pkt = gnrc_pkt_prepend(pkt, tmp);
+    }
+
+    /* add TX timestamp & test data */
+    _fill_payload(databuf, len, ztimer_now(ZTIMER_USEC));
+
+    res = !gnrc_netapi_dispatch_send(GNRC_NETTYPE_IPV6,
+                                     GNRC_NETREG_DEMUX_CTX_ALL,
+                                     pkt);
+    if (res) {
+        DEBUG("error: unable to send ICMPv6 echo request\n");
+        res = -EBADF;
+    }
+
+error_exit:
+    if (res) {
+        gnrc_pktbuf_release(pkt);
+    }
+    return res;
+}
+
+int gnrc_icmpv6_echo_rsp_handle(gnrc_pktsnip_t *pkt, size_t len,
+                                gnrc_icmpv6_echo_rsp_handle_cb_t cb, void *ctx)
+{
+    gnrc_pktsnip_t *ipv6, *icmpv6;
+    ipv6_hdr_t *ipv6_hdr;
+    uint32_t now = ztimer_now(ZTIMER_USEC);
+    uint32_t triptime = 0;
+    int corrupted = -1;
+
+    ipv6 = gnrc_pktsnip_search_type(pkt, GNRC_NETTYPE_IPV6);
+    icmpv6 = gnrc_pktsnip_search_type(pkt, GNRC_NETTYPE_ICMPV6);
+    if ((ipv6 == NULL) || (icmpv6 == NULL)) {
+        DEBUG("No IPv6 or ICMPv6 header found in reply");
+        return -EINVAL;
+    }
+    ipv6_hdr = ipv6->data;
+#ifdef MODULE_GNRC_IPV6_NIB
+    /* successful ping to neighbor (NIB handles case if ipv6->src is not a
+     * neighbor) can be taken as upper-layer hint for reachability:
+     * https://tools.ietf.org/html/rfc4861#section-7.3.1 */
+    gnrc_ipv6_nib_nc_mark_reachable(&ipv6_hdr->src);
+#endif
+
+    icmpv6_echo_t *icmpv6_hdr = icmpv6->data;
+    _check_payload(icmpv6_hdr + 1, len, now, &triptime, &corrupted);
+
+    return cb(pkt, corrupted, triptime, ctx);
+}
+
 /** @} */