packets: Use RARPs for learning packets.

[sliver-openvswitch.git] / lib / packets.c

diff --git a/lib/packets.c b/lib/packets.c
index a8208f5..9b61d04 100644 (file)
--- a/lib/packets.c
+++ b/lib/packets.c
@@ -120,27 +120,37 @@ eth_addr_from_string(const char *s, uint8_t ea[ETH_ADDR_LEN])
     }
 }
 
-/* Fills 'b' with an 802.2 SNAP packet with Ethernet source address 'eth_src',
- * the Nicira OUI as SNAP organization and 'snap_type' as SNAP type.  The text
- * string in 'tag' is enclosed as the packet payload.
- *
+/* Fills 'b' with a Reverse ARP packet with Ethernet source address 'eth_src'.
  * This function is used by Open vSwitch to compose packets in cases where
- * context is important but content doesn't (or shouldn't) matter.  For this
- * purpose, 'snap_type' should be a random number and 'tag' should be an
- * English phrase that explains the purpose of the packet.  (The English phrase
- * gives hapless admins running Wireshark the opportunity to figure out what's
- * going on.) */
+ * context is important but content doesn't (or shouldn't) matter.
+ *
+ * The returned packet has enough headroom to insert an 802.1Q VLAN header if
+ * desired. */
 void
-compose_benign_packet(struct ofpbuf *b, const char *tag, uint16_t snap_type,
-                      const uint8_t eth_src[ETH_ADDR_LEN])
+compose_benign_packet(struct ofpbuf *b, const uint8_t eth_src[ETH_ADDR_LEN])
 {
-    size_t tag_size = strlen(tag) + 1;
-    char *payload;
+    struct eth_header *eth;
+    struct rarp_header *rarp;
 
-    payload = snap_compose(b, eth_addr_broadcast, eth_src, 0x002320, snap_type,
-                           tag_size + ETH_ADDR_LEN);
-    memcpy(payload, tag, tag_size);
-    memcpy(payload + tag_size, eth_src, ETH_ADDR_LEN);
+    ofpbuf_clear(b);
+    ofpbuf_prealloc_tailroom(b, ETH_HEADER_LEN + VLAN_HEADER_LEN
+                             + RARP_HEADER_LEN);
+    ofpbuf_reserve(b, VLAN_HEADER_LEN);
+    eth = ofpbuf_put_uninit(b, sizeof *eth);
+    memcpy(eth->eth_dst, eth_addr_broadcast, ETH_ADDR_LEN);
+    memcpy(eth->eth_src, eth_src, ETH_ADDR_LEN);
+    eth->eth_type = htons(ETH_TYPE_RARP);
+
+    rarp = ofpbuf_put_uninit(b, sizeof *rarp);
+    rarp->hw_addr_space = htons(ARP_HTYPE_ETH);
+    rarp->proto_addr_space = htons(ETH_TYPE_IP);
+    rarp->hw_addr_length = ETH_ADDR_LEN;
+    rarp->proto_addr_length = sizeof rarp->src_proto_addr;
+    rarp->opcode = htons(RARP_REQUEST_REVERSE);
+    memcpy(rarp->src_hw_addr, eth_src, ETH_ADDR_LEN);
+    rarp->src_proto_addr = htonl(0);
+    memcpy(rarp->target_hw_addr, eth_src, ETH_ADDR_LEN);
+    rarp->target_proto_addr = htonl(0);
 }
 
 /* Insert VLAN header according to given TCI. Packet passed must be Ethernet
@@ -424,49 +434,6 @@ eth_compose(struct ofpbuf *b, const uint8_t eth_dst[ETH_ADDR_LEN],
     return data;
 }
 
-/* Populates 'b' with an Ethernet LLC+SNAP packet headed with the given
- * 'eth_dst', 'eth_src', 'snap_org', and 'snap_type'.  A payload of 'size'
- * bytes is allocated in 'b' and returned.  This payload may be populated with
- * appropriate information by the caller.
- *
- * The returned packet has enough headroom to insert an 802.1Q VLAN header if
- * desired. */
-void *
-snap_compose(struct ofpbuf *b, const uint8_t eth_dst[ETH_ADDR_LEN],
-             const uint8_t eth_src[ETH_ADDR_LEN],
-             unsigned int oui, uint16_t snap_type, size_t size)
-{
-    struct eth_header *eth;
-    struct llc_snap_header *llc_snap;
-    void *payload;
-
-    /* Compose basic packet structure.  (We need the payload size to stick into
-     * the 802.2 header.) */
-    ofpbuf_clear(b);
-    ofpbuf_prealloc_tailroom(b, ETH_HEADER_LEN + VLAN_HEADER_LEN
-                             + LLC_SNAP_HEADER_LEN + size);
-    ofpbuf_reserve(b, VLAN_HEADER_LEN);
-    eth = ofpbuf_put_zeros(b, ETH_HEADER_LEN);
-    llc_snap = ofpbuf_put_zeros(b, LLC_SNAP_HEADER_LEN);
-    payload = ofpbuf_put_uninit(b, size);
-
-    /* Compose 802.2 header. */
-    memcpy(eth->eth_dst, eth_dst, ETH_ADDR_LEN);
-    memcpy(eth->eth_src, eth_src, ETH_ADDR_LEN);
-    eth->eth_type = htons(b->size - ETH_HEADER_LEN);
-
-    /* Compose LLC, SNAP headers. */
-    llc_snap->llc.llc_dsap = LLC_DSAP_SNAP;
-    llc_snap->llc.llc_ssap = LLC_SSAP_SNAP;
-    llc_snap->llc.llc_cntl = LLC_CNTL_SNAP;
-    llc_snap->snap.snap_org[0] = oui >> 16;
-    llc_snap->snap.snap_org[1] = oui >> 8;
-    llc_snap->snap.snap_org[2] = oui;
-    llc_snap->snap.snap_type = htons(snap_type);
-
-    return payload;
-}
-
 static void
 packet_set_ipv4_addr(struct ofpbuf *packet, ovs_be32 *addr, ovs_be32 new_addr)
 {