static unsigned int packet_length(const struct sk_buff *skb,
struct net_device *dev)
{
unsigned int length = skb->len - dev->hard_header_len;
if (!skb_vlan_tag_present(skb) &&
eth_type_vlan(skb->protocol))
length -= VLAN_HLEN;
/* Don't subtract for multiple VLAN tags. Most (all?) drivers allow
* (ETH_LEN + VLAN_HLEN) in addition to the mtu value, but almost none
* account for 802.1ad. e.g. is_skb_forwardable().
*/
return length;
}
/**
* __skb_flow_dissect - extract the flow_keys struct and return it
* @skb: sk_buff to extract the flow from, can be NULL if the rest are specified
* @flow_dissector: list of keys to dissect
* @target_container: target structure to put dissected values into
* @data: raw buffer pointer to the packet, if NULL use skb->data
* @proto: protocol for which to get the flow, if @data is NULL use skb->protocol
* @nhoff: network header offset, if @data is NULL use skb_network_offset(skb)
* @hlen: packet header length, if @data is NULL use skb_headlen(skb)
*
* The function will try to retrieve individual keys into target specified
* by flow_dissector from either the skbuff or a raw buffer specified by the
* rest parameters.
*
* Caller must take care of zeroing target container memory.
*/
bool __skb_flow_dissect(const struct sk_buff *skb,
struct flow_dissector *flow_dissector,
void *target_container,
void *data, __be16 proto, int nhoff, int hlen,
unsigned int flags)
{
struct flow_dissector_key_control *key_control;
struct flow_dissector_key_basic *key_basic;
struct flow_dissector_key_addrs *key_addrs;
struct flow_dissector_key_ports *key_ports;
struct flow_dissector_key_icmp *key_icmp;
struct flow_dissector_key_tags *key_tags;
struct flow_dissector_key_vlan *key_vlan;
bool skip_vlan = false;
u8 ip_proto = 0;
bool ret;
if (!data) {
data = skb->data;
proto = skb_vlan_tag_present(skb) ?
skb->vlan_proto : skb->protocol;
nhoff = skb_network_offset(skb);
hlen = skb_headlen(skb);
}
/* It is ensured by skb_flow_dissector_init() that control key will
* be always present.
*/
key_control = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_CONTROL,
target_container);
/* It is ensured by skb_flow_dissector_init() that basic key will
* be always present.
*/
key_basic = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_BASIC,
target_container);
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_ETH_ADDRS)) {
struct ethhdr *eth = eth_hdr(skb);
struct flow_dissector_key_eth_addrs *key_eth_addrs;
key_eth_addrs = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_ETH_ADDRS,
target_container);
memcpy(key_eth_addrs, ð->h_dest, sizeof(*key_eth_addrs));
}
proto_again:
switch (proto) {
case htons(ETH_P_IP): {
const struct iphdr *iph;
struct iphdr _iph;
ip:
iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
if (!iph || iph->ihl < 5)
goto out_bad;
nhoff += iph->ihl * 4;
ip_proto = iph->protocol;
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_IPV4_ADDRS)) {
key_addrs = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_IPV4_ADDRS,
target_container);
memcpy(&key_addrs->v4addrs, &iph->saddr,
sizeof(key_addrs->v4addrs));
key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
}
if (ip_is_fragment(iph)) {
key_control->flags |= FLOW_DIS_IS_FRAGMENT;
if (iph->frag_off & htons(IP_OFFSET)) {
goto out_good;
} else {
key_control->flags |= FLOW_DIS_FIRST_FRAG;
if (!(flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG))
goto out_good;
}
}
__skb_flow_dissect_ipv4(skb, flow_dissector,
target_container, data, iph);
if (flags & FLOW_DISSECTOR_F_STOP_AT_L3)
goto out_good;
break;
}
case htons(ETH_P_IPV6): {
const struct ipv6hdr *iph;
struct ipv6hdr _iph;
ipv6:
iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
if (!iph)
goto out_bad;
ip_proto = iph->nexthdr;
nhoff += sizeof(struct ipv6hdr);
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_IPV6_ADDRS)) {
key_addrs = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_IPV6_ADDRS,
target_container);
memcpy(&key_addrs->v6addrs, &iph->saddr,
sizeof(key_addrs->v6addrs));
key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
}
if ((dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_FLOW_LABEL) ||
(flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)) &&
ip6_flowlabel(iph)) {
__be32 flow_label = ip6_flowlabel(iph);
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_FLOW_LABEL)) {
key_tags = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_FLOW_LABEL,
target_container);
key_tags->flow_label = ntohl(flow_label);
}
if (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)
goto out_good;
}
__skb_flow_dissect_ipv6(skb, flow_dissector,
target_container, data, iph);
if (flags & FLOW_DISSECTOR_F_STOP_AT_L3)
goto out_good;
break;
}
case htons(ETH_P_8021AD):
case htons(ETH_P_8021Q): {
const struct vlan_hdr *vlan;
struct vlan_hdr _vlan;
bool vlan_tag_present = skb && skb_vlan_tag_present(skb);
if (vlan_tag_present)
proto = skb->protocol;
if (!vlan_tag_present || eth_type_vlan(skb->protocol)) {
vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan),
data, hlen, &_vlan);
if (!vlan)
goto out_bad;
proto = vlan->h_vlan_encapsulated_proto;
nhoff += sizeof(*vlan);
if (skip_vlan)
goto proto_again;
}
skip_vlan = true;
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_VLAN)) {
key_vlan = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_VLAN,
target_container);
if (vlan_tag_present) {
key_vlan->vlan_id = skb_vlan_tag_get_id(skb);
key_vlan->vlan_priority =
(skb_vlan_tag_get_prio(skb) >> VLAN_PRIO_SHIFT);
} else {
key_vlan->vlan_id = ntohs(vlan->h_vlan_TCI) &
VLAN_VID_MASK;
key_vlan->vlan_priority =
(ntohs(vlan->h_vlan_TCI) &
VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;
}
}
goto proto_again;
}
case htons(ETH_P_PPP_SES): {
struct {
struct pppoe_hdr hdr;
__be16 proto;
} *hdr, _hdr;
hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
if (!hdr)
goto out_bad;
proto = hdr->proto;
nhoff += PPPOE_SES_HLEN;
switch (proto) {
case htons(PPP_IP):
goto ip;
case htons(PPP_IPV6):
goto ipv6;
default:
goto out_bad;
}
}
case htons(ETH_P_TIPC): {
struct {
__be32 pre[3];
__be32 srcnode;
} *hdr, _hdr;
hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
if (!hdr)
goto out_bad;
if (dissector_uses_key(flow_dissector,
FLOW_DISSECTOR_KEY_TIPC_ADDRS)) {
key_addrs = skb_flow_dissector_target(flow_dissector,
FLOW_DISSECTOR_KEY_TIPC_ADDRS,
target_container);
key_addrs->tipcaddrs.srcnode = hdr->srcnode;
key_control->addr_type = FLOW_DISSECTOR_KEY_TIPC_ADDRS;
}
goto out_good;
}
case htons(ETH_P_MPLS_UC):
case htons(ETH_P_MPLS_MC):
mpls:
switch (__skb_flow_dissect_mpls(skb, flow_dissector,
target_container, data,
nhoff, hlen)) {
case FLOW_DISSECT_RET_OUT_GOOD:
goto out_good;
case FLOW_DISSECT_RET_OUT_BAD:
default:
goto out_bad;
}
case htons(ETH_P_FCOE):
if ((hlen - nhoff) < FCOE_HEADER_LEN)
goto out_bad;
nhoff += FCOE_HEADER_LEN;
goto out_good;
case htons(ETH_P_ARP):
case htons(ETH_P_RARP):
switch (__skb_flow_dissect_arp(skb, flow_dissector,
target_container, data,
nhoff, hlen)) {
case FLOW_DISSECT_RET_OUT_GOOD:
goto out_good;
case FLOW_DISSECT_RET_OUT_BAD:
default:
goto out_bad;
}
default:
goto out_bad;
}
