For SNAT, don't store the pre-fragment L2 header before actions are applied.
[sliver-openvswitch.git] / lib / flow.c
index 2d428b4..cb6b32c 100644 (file)
  * advertising or publicity pertaining to the Software or any
  * derivatives without specific, written prior permission.
  */
+#include <config.h>
 #include <sys/types.h>
 #include "flow.h"
 #include <inttypes.h>
 #include <netinet/in.h>
 #include <string.h>
-#include "buffer.h"
 #include "hash.h"
-#include "openflow.h"
+#include "ofpbuf.h"
+#include "openflow/openflow.h"
 #include "packets.h"
 
 #include "vlog.h"
 #define THIS_MODULE VLM_flow
 
-void
-flow_extract(struct buffer *packet, uint16_t in_port, struct flow *flow)
+static struct ip_header *
+pull_ip(struct ofpbuf *packet)
 {
-    struct buffer b = *packet;
-    struct eth_header *eth;
+    if (packet->size >= IP_HEADER_LEN) {
+        struct ip_header *ip = packet->data;
+        int ip_len = IP_IHL(ip->ip_ihl_ver) * 4;
+        if (ip_len >= IP_HEADER_LEN && packet->size >= ip_len) {
+            return ofpbuf_pull(packet, ip_len);
+        }
+    }
+    return NULL;
+}
 
-    if (b.size < ETH_TOTAL_MIN) {
-        VLOG_WARN("packet length %d less than minimum size %d",
-                  b.size, ETH_TOTAL_MIN);
+static struct tcp_header *
+pull_tcp(struct ofpbuf *packet) 
+{
+    if (packet->size >= TCP_HEADER_LEN) {
+        struct tcp_header *tcp = packet->data;
+        int tcp_len = TCP_OFFSET(tcp->tcp_ctl) * 4;
+        if (tcp_len >= TCP_HEADER_LEN && packet->size >= tcp_len) {
+            return ofpbuf_pull(packet, tcp_len);
+        }
     }
+    return NULL;
+}
+
+static struct udp_header *
+pull_udp(struct ofpbuf *packet) 
+{
+    return ofpbuf_try_pull(packet, UDP_HEADER_LEN);
+}
+
+static struct icmp_header *
+pull_icmp(struct ofpbuf *packet) 
+{
+    return ofpbuf_try_pull(packet, ICMP_HEADER_LEN);
+}
+
+static struct eth_header *
+pull_eth(struct ofpbuf *packet) 
+{
+    return ofpbuf_try_pull(packet, ETH_HEADER_LEN);
+}
+
+static struct vlan_header *
+pull_vlan(struct ofpbuf *packet)
+{
+    return ofpbuf_try_pull(packet, VLAN_HEADER_LEN);
+}
+
+/* Returns 1 if 'packet' is an IP fragment, 0 otherwise. */
+int
+flow_extract(struct ofpbuf *packet, uint16_t in_port, struct flow *flow)
+{
+    struct ofpbuf b = *packet;
+    struct eth_header *eth;
+    int retval = 0;
 
     memset(flow, 0, sizeof *flow);
+    flow->dl_vlan = htons(OFP_VLAN_NONE);
     flow->in_port = htons(in_port);
 
     packet->l2 = b.data;
     packet->l3 = NULL;
     packet->l4 = NULL;
+    packet->l7 = NULL;
 
-    eth = buffer_at(&b, 0, sizeof *eth);
+    eth = pull_eth(&b);
     if (eth) {
-        buffer_pull(&b, ETH_HEADER_LEN);
         if (ntohs(eth->eth_type) >= OFP_DL_TYPE_ETH2_CUTOFF) {
             /* This is an Ethernet II frame */
             flow->dl_type = eth->eth_type;
         } else {
             /* This is an 802.2 frame */
-            struct llc_snap_header *h = buffer_at(&b, 0, sizeof *h);
+            struct llc_snap_header *h = ofpbuf_at(&b, 0, sizeof *h);
             if (h == NULL) {
-                return;
+                return 0;
             }
             if (h->llc.llc_dsap == LLC_DSAP_SNAP
                 && h->llc.llc_ssap == LLC_SSAP_SNAP
@@ -79,64 +128,74 @@ flow_extract(struct buffer *packet, uint16_t in_port, struct flow *flow)
                 && !memcmp(h->snap.snap_org, SNAP_ORG_ETHERNET,
                            sizeof h->snap.snap_org)) {
                 flow->dl_type = h->snap.snap_type;
-                buffer_pull(&b, sizeof *h);
+                ofpbuf_pull(&b, sizeof *h);
             } else {
-                flow->dl_type = OFP_DL_TYPE_NOT_ETH_TYPE;
-                buffer_pull(&b, sizeof(struct llc_header));
+                flow->dl_type = htons(OFP_DL_TYPE_NOT_ETH_TYPE);
+                ofpbuf_pull(&b, sizeof(struct llc_header));
             }
         }
 
         /* Check for a VLAN tag */
-        if (flow->dl_type != htons(ETH_TYPE_VLAN)) {
-            flow->dl_vlan = htons(OFP_VLAN_NONE);
-        } else {
-            struct vlan_header *vh = buffer_at(&b, 0, sizeof *vh);
-            flow->dl_type = vh->vlan_next_type;
-            flow->dl_vlan = vh->vlan_tci & htons(VLAN_VID);
-            buffer_pull(&b, sizeof *vh);
+        if (flow->dl_type == htons(ETH_TYPE_VLAN)) {
+            struct vlan_header *vh = pull_vlan(&b);
+            if (vh) {
+                flow->dl_type = vh->vlan_next_type;
+                flow->dl_vlan = vh->vlan_tci & htons(VLAN_VID_MASK);
+            }
         }
         memcpy(flow->dl_src, eth->eth_src, ETH_ADDR_LEN);
         memcpy(flow->dl_dst, eth->eth_dst, ETH_ADDR_LEN);
 
         packet->l3 = b.data;
         if (flow->dl_type == htons(ETH_TYPE_IP)) {
-            const struct ip_header *nh = buffer_at(&b, 0, sizeof *nh);
+            const struct ip_header *nh = pull_ip(&b);
             if (nh) {
-                int ip_len = IP_IHL(nh->ip_ihl_ver) * 4;
-                if (ip_len < IP_HEADER_LEN) {
-                    return;
-                }
-
                 flow->nw_src = nh->ip_src;
                 flow->nw_dst = nh->ip_dst;
                 flow->nw_proto = nh->ip_proto;
-                if (flow->nw_proto == IP_TYPE_TCP
-                    || flow->nw_proto == IP_TYPE_UDP) {
-                    const struct udp_header *th;
-                    th = packet->l4 = buffer_at(&b, ip_len, sizeof *th);
-                    if (th) {
-                        flow->tp_src = th->udp_src;
-                        flow->tp_dst = th->udp_dst;
-                    } else {
-                        /* Avoid tricking other code into thinking that this
-                         * packet has an L4 header. */
-                        flow->nw_proto = 0;
+                packet->l4 = b.data;
+                if (!IP_IS_FRAGMENT(nh->ip_frag_off)) {
+                    if (flow->nw_proto == IP_TYPE_TCP) {
+                        const struct tcp_header *tcp = pull_tcp(&b);
+                        if (tcp) {
+                            flow->tp_src = tcp->tcp_src;
+                            flow->tp_dst = tcp->tcp_dst;
+                            packet->l7 = b.data;
+                        } else {
+                            /* Avoid tricking other code into thinking that
+                             * this packet has an L4 header. */
+                            flow->nw_proto = 0;
+                        }
+                    } else if (flow->nw_proto == IP_TYPE_UDP) {
+                        const struct udp_header *udp = pull_udp(&b);
+                        if (udp) {
+                            flow->tp_src = udp->udp_src;
+                            flow->tp_dst = udp->udp_dst;
+                            packet->l7 = b.data;
+                        } else {
+                            /* Avoid tricking other code into thinking that
+                             * this packet has an L4 header. */
+                            flow->nw_proto = 0;
+                        }
+                    } else if (flow->nw_proto == IP_TYPE_ICMP) {
+                        const struct icmp_header *icmp = pull_icmp(&b);
+                        if (icmp) {
+                            flow->icmp_type = htons(icmp->icmp_type);
+                            flow->icmp_code = htons(icmp->icmp_code);
+                            packet->l7 = b.data;
+                        } else {
+                            /* Avoid tricking other code into thinking that
+                             * this packet has an L4 header. */
+                            flow->nw_proto = 0;
+                        }
                     }
+                } else {
+                    retval = 1;
                 }
             }
-        } else if (flow->dl_type == htons(ETH_TYPE_ARP)) {
-            const struct arp_eth_header *ah = buffer_at(&b, 0, sizeof *ah);
-            if (ah && ah->ar_hrd == htons(ARP_HRD_ETHERNET)
-                && ah->ar_pro == htons(ARP_PRO_IP)
-                && ah->ar_hln == ETH_ADDR_LEN
-                && ah->ar_pln == sizeof flow->nw_src)
-            {
-                /* check if sha/tha match dl_src/dl_dst? */
-                flow->nw_src = ah->ar_spa;
-                flow->nw_dst = ah->ar_tpa;
-            }
         }
     }
+    return retval;
 }
 
 void