#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/in6.h>
+#include <linux/if_arp.h>
#include <linux/if_vlan.h>
#include <net/inet_ecn.h>
#include <net/ip.h>
struct ethhdr *eh;
/* Verify we were given a vlan packet */
- if (vh->h_vlan_proto != htons(ETH_P_8021Q))
+ if (vh->h_vlan_proto != htons(ETH_P_8021Q) || skb->len < VLAN_ETH_HLEN)
return skb;
if (OVS_CB(skb)->ip_summed == OVS_CSUM_COMPLETE)
if (skb->protocol == htons(ETH_P_8021Q)) {
/* Modify vlan id, but maintain other TCI values */
- struct vlan_ethhdr *vh = vlan_eth_hdr(skb);
- __be16 old_tci = vh->h_vlan_TCI;
+ struct vlan_ethhdr *vh;
+ __be16 old_tci;
+
+ if (skb->len < VLAN_ETH_HLEN)
+ return skb;
+
+ vh = vlan_eth_hdr(skb);
+ old_tci = vh->h_vlan_TCI;
vh->h_vlan_TCI = htons((ntohs(vh->h_vlan_TCI) & ~mask) | tci);
csum_unfold(*sum)));
}
+static bool is_ip(struct sk_buff *skb, const struct odp_flow_key *key)
+{
+ return (key->dl_type == htons(ETH_P_IP) &&
+ skb->transport_header > skb->network_header);
+}
+
+static __sum16 *get_l4_checksum(struct sk_buff *skb, const struct odp_flow_key *key)
+{
+ int transport_len = skb->len - skb_transport_offset(skb);
+ if (key->nw_proto == IPPROTO_TCP) {
+ if (likely(transport_len >= sizeof(struct tcphdr)))
+ return &tcp_hdr(skb)->check;
+ } else if (key->nw_proto == IPPROTO_UDP) {
+ if (likely(transport_len >= sizeof(struct udphdr)))
+ return &udp_hdr(skb)->check;
+ }
+ return NULL;
+}
+
static struct sk_buff *set_nw_addr(struct sk_buff *skb,
const struct odp_flow_key *key,
const struct odp_action_nw_addr *a,
gfp_t gfp)
{
- if (key->dl_type != htons(ETH_P_IP))
+ struct iphdr *nh;
+ __sum16 *check;
+ __be32 *nwaddr;
+
+ if (unlikely(!is_ip(skb, key)))
return skb;
skb = make_writable(skb, 0, gfp);
- if (skb) {
- struct iphdr *nh = ip_hdr(skb);
- u32 *f = a->type == ODPAT_SET_NW_SRC ? &nh->saddr : &nh->daddr;
- u32 old = *f;
- u32 new = a->nw_addr;
-
- if (key->nw_proto == IPPROTO_TCP) {
- struct tcphdr *th = tcp_hdr(skb);
- update_csum(&th->check, skb, old, new, 1);
- } else if (key->nw_proto == IPPROTO_UDP) {
- struct udphdr *th = udp_hdr(skb);
- update_csum(&th->check, skb, old, new, 1);
- }
- update_csum(&nh->check, skb, old, new, 0);
- *f = new;
- }
+ if (unlikely(!skb))
+ return NULL;
+
+ nh = ip_hdr(skb);
+ nwaddr = a->type == ODPAT_SET_NW_SRC ? &nh->saddr : &nh->daddr;
+
+ check = get_l4_checksum(skb, key);
+ if (likely(check))
+ update_csum(check, skb, *nwaddr, a->nw_addr, 1);
+ update_csum(&nh->check, skb, *nwaddr, a->nw_addr, 0);
+
+ *nwaddr = a->nw_addr;
+
return skb;
}
const struct odp_action_nw_tos *a,
gfp_t gfp)
{
- if (key->dl_type != htons(ETH_P_IP))
+ if (unlikely(!is_ip(skb, key)))
return skb;
skb = make_writable(skb, 0, gfp);
/* Set the DSCP bits and preserve the ECN bits. */
new = a->nw_tos | (nh->tos & INET_ECN_MASK);
- update_csum(&nh->check, skb, htons((uint16_t)old),
- htons((uint16_t)new), 0);
+ update_csum(&nh->check, skb, htons((u16)old),
+ htons((u16)new), 0);
*f = new;
}
return skb;
const struct odp_flow_key *key,
const struct odp_action_tp_port *a, gfp_t gfp)
{
- int check_ofs;
+ struct udphdr *th;
+ __sum16 *check;
+ __be16 *port;
- if (key->dl_type != htons(ETH_P_IP))
+ if (unlikely(!is_ip(skb, key)))
return skb;
- if (key->nw_proto == IPPROTO_TCP)
- check_ofs = offsetof(struct tcphdr, check);
- else if (key->nw_proto == IPPROTO_UDP)
- check_ofs = offsetof(struct udphdr, check);
- else
+ skb = make_writable(skb, 0, gfp);
+ if (unlikely(!skb))
+ return NULL;
+
+ /* Must follow make_writable() since that can move the skb data. */
+ check = get_l4_checksum(skb, key);
+ if (unlikely(!check))
return skb;
- skb = make_writable(skb, 0, gfp);
- if (skb) {
- struct udphdr *th = udp_hdr(skb);
- u16 *f = a->type == ODPAT_SET_TP_SRC ? &th->source : &th->dest;
- u16 old = *f;
- u16 new = a->tp_port;
- update_csum((u16*)(skb_transport_header(skb) + check_ofs),
- skb, old, new, 0);
- *f = new;
- }
+ /*
+ * Update port and checksum.
+ *
+ * This is OK because source and destination port numbers are at the
+ * same offsets in both UDP and TCP headers, and get_l4_checksum() only
+ * supports those protocols.
+ */
+ th = udp_hdr(skb);
+ port = a->type == ODPAT_SET_TP_SRC ? &th->source : &th->dest;
+ update_csum(check, skb, *port, a->tp_port, 0);
+ *port = a->tp_port;
+
return skb;
}
+/**
+ * is_spoofed_arp - check for invalid ARP packet
+ *
+ * @skb: skbuff containing an Ethernet packet, with network header pointing
+ * just past the Ethernet and optional 802.1Q header.
+ * @key: flow key extracted from @skb by flow_extract()
+ *
+ * Returns true if @skb is an invalid Ethernet+IPv4 ARP packet: one with screwy
+ * or truncated header fields or one whose inner and outer Ethernet address
+ * differ.
+ */
+static bool is_spoofed_arp(struct sk_buff *skb, const struct odp_flow_key *key)
+{
+ struct arp_eth_header *arp;
+
+ if (key->dl_type != htons(ETH_P_ARP))
+ return false;
+
+ if (skb_network_offset(skb) + sizeof(struct arp_eth_header) > skb->len)
+ return true;
+
+ arp = (struct arp_eth_header *)skb_network_header(skb);
+ return (arp->ar_hrd != htons(ARPHRD_ETHER) ||
+ arp->ar_pro != htons(ETH_P_IP) ||
+ arp->ar_hln != ETH_ALEN ||
+ arp->ar_pln != 4 ||
+ compare_ether_addr(arp->ar_sha, eth_hdr(skb)->h_source));
+}
+
static void do_output(struct datapath *dp, struct sk_buff *skb, int out_port)
{
struct dp_port *p;
case ODPAT_POP_PRIORITY:
skb->priority = priority;
break;
+
+ case ODPAT_DROP_SPOOFED_ARP:
+ if (unlikely(is_spoofed_arp(skb, key)))
+ goto exit;
+ break;
}
if (!skb)
return -ENOMEM;
}
+exit:
if (prev_port != -1)
do_output(dp, skb, prev_port);
else