sys/net/sock: add sock_aux_ttl

RIOT-OS · Jul 18, 2023 · 5a0550e · 5a0550e
1 parent ceaf6bd
commit 5a0550e
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diff --git a/makefiles/pseudomodules.inc.mk b/makefiles/pseudomodules.inc.mk
@@ -513,6 +513,7 @@ PSEUDOMODULES += sock_async
 PSEUDOMODULES += sock_aux_local
 PSEUDOMODULES += sock_aux_rssi
 PSEUDOMODULES += sock_aux_timestamp
+PSEUDOMODULES += sock_aux_ttl
 PSEUDOMODULES += sock_dtls
 PSEUDOMODULES += sock_ip
 PSEUDOMODULES += sock_tcp

diff --git a/sys/include/net/sock.h b/sys/include/net/sock.h
@@ -319,6 +319,21 @@ enum {
      * @ref sock_dtls_aux_tx_t::local.
      */
     SOCK_AUX_SET_LOCAL = (1LU << 3),
+    /**
+     * @brief   Flag to request the TTL value of received frame
+     *
+     * @note    Select module `sock_aux_ttl` and a compatible network stack to
+     *          use this
+     *
+     * Set this flag in the auxiliary data structure prior to the call of
+     * @ref sock_udp_recv_aux / @ref sock_ip_recv_aux / etc. to request the
+     * TTL value of a received frame. This flag will be cleared if the
+     * time to live was stored, otherwise it remains set.
+     *
+     * Depending on the family of the socket, the TTL value will be stored in
+     * @ref sock_udp_aux_rx_t::ttl or @ref sock_dtls_aux_rx_t::ttl.
+     */
+    SOCK_AUX_GET_TTL = (1LU << 4),
 };
 
 /**

diff --git a/sys/include/net/sock/udp.h b/sys/include/net/sock/udp.h
@@ -332,6 +332,14 @@ typedef struct {
      */
     int16_t rssi;
 #endif /* MODULE_SOCK_AUX_RSSI */
+#if defined(MODULE_SOCK_AUX_TTL) || defined(DOXYGEN)
+    /**
+     * @brief   TTL value of the received frame
+     *
+     * @see SOCK_AUX_GET_TTL
+     */
+    uint8_t ttl;
+#endif /* MODULE_SOCK_AUX_TTL */
     sock_aux_flags_t flags; /**< Flags used request information */
 } sock_udp_aux_rx_t;
 

diff --git a/sys/net/gnrc/sock/udp/gnrc_sock_udp.c b/sys/net/gnrc/sock/udp/gnrc_sock_udp.c
@@ -305,6 +305,16 @@ ssize_t sock_udp_recv_buf_aux(sock_udp_t *sock, void **data, void **buf_ctx,
     if ((aux != NULL) && (_aux.flags & GNRC_SOCK_RECV_AUX_FLAG_RSSI)) {
         aux->flags &= ~SOCK_AUX_GET_RSSI;
     }
+#endif
+#if IS_USED(MODULE_SOCK_AUX_TTL)
+    if ((aux != NULL) && (aux->flags & SOCK_AUX_GET_TTL)) {
+        gnrc_pktsnip_t *ip = gnrc_pktsnip_search_type(pkt, GNRC_NETTYPE_IPV6);
+        if (ip) {
+            ipv6_hdr_t *ip_hdr = ip->data;
+            aux->ttl = ip_hdr->hl;
+            aux->flags &= ~SOCK_AUX_GET_TTL;
+        }
+    }
 #endif
     *data = pkt->data;
     *buf_ctx = pkt;