#include <linux/ip.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
+#include <linux/llc.h>
#include <linux/module.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include "openflow/openflow.h"
#include "compat.h"
-#include "snap.h"
struct kmem_cache *flow_cache;
}
EXPORT_SYMBOL(print_flow);
+#define SNAP_OUI_LEN 3
+
+struct eth_snap_hdr
+{
+ struct ethhdr eth;
+ uint8_t dsap; /* Always 0xAA */
+ uint8_t ssap; /* Always 0xAA */
+ uint8_t ctrl;
+ uint8_t oui[SNAP_OUI_LEN];
+ uint16_t ethertype;
+} __attribute__ ((packed));
+
+static int is_snap(const struct eth_snap_hdr *esh)
+{
+ return (esh->dsap == LLC_SAP_SNAP
+ && esh->ssap == LLC_SAP_SNAP
+ && !memcmp(esh->oui, "\0\0\0", 3));
+}
+
+static int iphdr_ok(struct sk_buff *skb)
+{
+ int nh_ofs = skb_network_offset(skb);
+ if (skb->len >= nh_ofs + sizeof(struct iphdr)) {
+ int ip_len = ip_hdrlen(skb);
+ return (ip_len >= sizeof(struct iphdr)
+ && pskb_may_pull(skb, nh_ofs + ip_len));
+ }
+ return 0;
+}
+
static int tcphdr_ok(struct sk_buff *skb)
{
int th_ofs = skb_transport_offset(skb);
- if (skb->len >= th_ofs + sizeof(struct tcphdr)) {
+ if (pskb_may_pull(skb, th_ofs + sizeof(struct tcphdr))) {
int tcp_len = tcp_hdrlen(skb);
return (tcp_len >= sizeof(struct tcphdr)
&& skb->len >= th_ofs + tcp_len);
static int udphdr_ok(struct sk_buff *skb)
{
int th_ofs = skb_transport_offset(skb);
- return skb->len >= th_ofs + sizeof(struct udphdr);
+ return pskb_may_pull(skb, th_ofs + sizeof(struct udphdr));
}
/* Parses the Ethernet frame in 'skb', which was received on 'in_port',
int flow_extract(struct sk_buff *skb, uint16_t in_port,
struct sw_flow_key *key)
{
- struct ethhdr *mac;
- int nh_ofs, th_ofs;
+ struct ethhdr *eth;
+ struct eth_snap_hdr *esh;
int retval = 0;
+ int nh_ofs;
+ memset(key, 0, sizeof *key);
+ key->dl_vlan = htons(OFP_VLAN_NONE);
key->in_port = htons(in_port);
- key->pad = 0;
- key->wildcards = 0;
- key->nw_src_mask = 0;
- key->nw_dst_mask = 0;
-
- /* This code doesn't check that skb->len is long enough to contain the
- * MAC or network header. With a 46-byte minimum length frame this
- * assumption is always correct. */
-
- /* Doesn't verify checksums. Should it? */
-
- /* Data link layer. We only support Ethernet. */
- mac = eth_hdr(skb);
- nh_ofs = sizeof(struct ethhdr);
- if (likely(ntohs(mac->h_proto) >= OFP_DL_TYPE_ETH2_CUTOFF)) {
- /* This is an Ethernet II frame */
- key->dl_type = mac->h_proto;
+
+ if (skb->len < sizeof *eth)
+ return 0;
+ if (!pskb_may_pull(skb, skb->len >= 64 ? 64 : skb->len)) {
+ return 0;
+ }
+
+ eth = eth_hdr(skb);
+ esh = (struct eth_snap_hdr *) eth;
+ nh_ofs = sizeof *eth;
+ if (likely(ntohs(eth->h_proto) >= OFP_DL_TYPE_ETH2_CUTOFF))
+ key->dl_type = eth->h_proto;
+ else if (skb->len >= sizeof *esh && is_snap(esh)) {
+ key->dl_type = esh->ethertype;
+ nh_ofs = sizeof *esh;
} else {
- /* This is an 802.2 frame */
- if (snap_get_ethertype(skb, &key->dl_type) != -EINVAL) {
- nh_ofs += sizeof(struct snap_hdr);
- } else {
- key->dl_type = htons(OFP_DL_TYPE_NOT_ETH_TYPE);
- nh_ofs += sizeof(struct llc_pdu_un);
+ key->dl_type = htons(OFP_DL_TYPE_NOT_ETH_TYPE);
+ if (skb->len >= nh_ofs + sizeof(struct llc_pdu_un)) {
+ nh_ofs += sizeof(struct llc_pdu_un);
}
}
/* Check for a VLAN tag */
- if (likely(key->dl_type != htons(ETH_P_8021Q))) {
- key->dl_vlan = htons(OFP_VLAN_NONE);
- } else {
- struct vlan_hdr *vh = (struct vlan_hdr *)(skb_mac_header(skb) + nh_ofs);
+ if (key->dl_type == htons(ETH_P_8021Q) &&
+ skb->len >= nh_ofs + sizeof(struct vlan_hdr)) {
+ struct vlan_hdr *vh = (struct vlan_hdr*)(skb->data + nh_ofs);
key->dl_type = vh->h_vlan_encapsulated_proto;
key->dl_vlan = vh->h_vlan_TCI & htons(VLAN_VID_MASK);
- nh_ofs += sizeof(*vh);
+ nh_ofs += sizeof(struct vlan_hdr);
}
- memcpy(key->dl_src, mac->h_source, ETH_ALEN);
- memcpy(key->dl_dst, mac->h_dest, ETH_ALEN);
+ memcpy(key->dl_src, eth->h_source, ETH_ALEN);
+ memcpy(key->dl_dst, eth->h_dest, ETH_ALEN);
skb_set_network_header(skb, nh_ofs);
/* Network layer. */
- if (likely(key->dl_type == htons(ETH_P_IP))) {
+ if (key->dl_type == htons(ETH_P_IP) && iphdr_ok(skb)) {
struct iphdr *nh = ip_hdr(skb);
+ int th_ofs = nh_ofs + nh->ihl * 4;
key->nw_src = nh->saddr;
key->nw_dst = nh->daddr;
key->nw_proto = nh->protocol;
- th_ofs = nh_ofs + nh->ihl * 4;
skb_set_transport_header(skb, th_ofs);
/* Transport layer. */
/* Avoid tricking other code into
* thinking that this packet has an L4
* header. */
- goto no_proto;
+ key->nw_proto = 0;
}
} else if (key->nw_proto == IPPROTO_UDP) {
if (udphdr_ok(skb)) {
/* Avoid tricking other code into
* thinking that this packet has an L4
* header. */
- goto no_proto;
+ key->nw_proto = 0;
}
- } else {
- goto no_th;
}
} else {
retval = 1;
- goto no_th;
}
-
- return 0;
+ } else {
+ skb_reset_transport_header(skb);
}
-
- key->nw_src = 0;
- key->nw_dst = 0;
-
-no_proto:
- key->nw_proto = 0;
-
-no_th:
- key->tp_src = 0;
- key->tp_dst = 0;
return retval;
}
projects / openvswitch / commitdiff