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linux/net/openvswitch/flow.c
Paul Blakey 95a7233c45 net: openvswitch: Set OvS recirc_id from tc chain index 
Offloaded OvS datapath rules are translated one to one to tc rules,
for example the following simplified OvS rule:

recirc_id(0),in_port(dev1),eth_type(0x0800),ct_state(-trk) actions:ct(),recirc(2)

Will be translated to the following tc rule:

$ tc filter add dev dev1 ingress \
	    prio 1 chain 0 proto ip \
		flower tcp ct_state -trk \
		action ct pipe \
		action goto chain 2

Received packets will first travel though tc, and if they aren't stolen
by it, like in the above rule, they will continue to OvS datapath.
Since we already did some actions (action ct in this case) which might
modify the packets, and updated action stats, we would like to continue
the proccessing with the correct recirc_id in OvS (here recirc_id(2))
where we left off.

To support this, introduce a new skb extension for tc, which
will be used for translating tc chain to ovs recirc_id to
handle these miss cases. Last tc chain index will be set
by tc goto chain action and read by OvS datapath.

Signed-off-by: Paul Blakey <paulb@mellanox.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-09-06 14:59:18 +02:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2007-2014 Nicira, Inc.
*/
#include <linux/uaccess.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/if_ether.h>
#include <linux/if_vlan.h>
#include <net/llc_pdu.h>
#include <linux/kernel.h>
#include <linux/jhash.h>
#include <linux/jiffies.h>
#include <linux/llc.h>
#include <linux/module.h>
#include <linux/in.h>
#include <linux/rcupdate.h>
#include <linux/cpumask.h>
#include <linux/if_arp.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/mpls.h>
#include <linux/sctp.h>
#include <linux/smp.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/icmp.h>
#include <linux/icmpv6.h>
#include <linux/rculist.h>
#include <net/ip.h>
#include <net/ip_tunnels.h>
#include <net/ipv6.h>
#include <net/mpls.h>
#include <net/ndisc.h>
#include <net/nsh.h>
#include "conntrack.h"
#include "datapath.h"
#include "flow.h"
#include "flow_netlink.h"
#include "vport.h"
u64 ovs_flow_used_time(unsigned long flow_jiffies)
{
struct timespec64 cur_ts;
u64 cur_ms, idle_ms;
ktime_get_ts64(&cur_ts);
idle_ms = jiffies_to_msecs(jiffies - flow_jiffies);
cur_ms = (u64)(u32)cur_ts.tv_sec * MSEC_PER_SEC +
cur_ts.tv_nsec / NSEC_PER_MSEC;
return cur_ms - idle_ms;
}
#define TCP_FLAGS_BE16(tp) (*(__be16 *)&tcp_flag_word(tp) & htons(0x0FFF))
void ovs_flow_stats_update(struct sw_flow *flow, __be16 tcp_flags,
const struct sk_buff *skb)
{
struct sw_flow_stats *stats;
unsigned int cpu = smp_processor_id();
int len = skb->len + (skb_vlan_tag_present(skb) ? VLAN_HLEN : 0);
stats = rcu_dereference(flow->stats[cpu]);
/* Check if already have CPU-specific stats. */
if (likely(stats)) {
spin_lock(&stats->lock);
/* Mark if we write on the pre-allocated stats. */
if (cpu == 0 && unlikely(flow->stats_last_writer != cpu))
flow->stats_last_writer = cpu;
} else {
stats = rcu_dereference(flow->stats[0]); /* Pre-allocated. */
spin_lock(&stats->lock);
/* If the current CPU is the only writer on the
* pre-allocated stats keep using them.
*/
if (unlikely(flow->stats_last_writer != cpu)) {
/* A previous locker may have already allocated the
* stats, so we need to check again. If CPU-specific
* stats were already allocated, we update the pre-
* allocated stats as we have already locked them.
*/
if (likely(flow->stats_last_writer != -1) &&
likely(!rcu_access_pointer(flow->stats[cpu]))) {
/* Try to allocate CPU-specific stats. */
struct sw_flow_stats *new_stats;
new_stats =
kmem_cache_alloc_node(flow_stats_cache,
GFP_NOWAIT |
__GFP_THISNODE |
__GFP_NOWARN |
__GFP_NOMEMALLOC,
numa_node_id());
if (likely(new_stats)) {
new_stats->used = jiffies;
new_stats->packet_count = 1;
new_stats->byte_count = len;
new_stats->tcp_flags = tcp_flags;
spin_lock_init(&new_stats->lock);
rcu_assign_pointer(flow->stats[cpu],
new_stats);
cpumask_set_cpu(cpu, &flow->cpu_used_mask);
goto unlock;
}
}
flow->stats_last_writer = cpu;
}
}
stats->used = jiffies;
stats->packet_count++;
stats->byte_count += len;
stats->tcp_flags |= tcp_flags;
unlock:
spin_unlock(&stats->lock);
}
/* Must be called with rcu_read_lock or ovs_mutex. */
void ovs_flow_stats_get(const struct sw_flow *flow,
struct ovs_flow_stats *ovs_stats,
unsigned long *used, __be16 *tcp_flags)
{
int cpu;
*used = 0;
*tcp_flags = 0;
memset(ovs_stats, 0, sizeof(*ovs_stats));
/* We open code this to make sure cpu 0 is always considered */
for (cpu = 0; cpu < nr_cpu_ids; cpu = cpumask_next(cpu, &flow->cpu_used_mask)) {
struct sw_flow_stats *stats = rcu_dereference_ovsl(flow->stats[cpu]);
if (stats) {
/* Local CPU may write on non-local stats, so we must
* block bottom-halves here.
*/
spin_lock_bh(&stats->lock);
if (!*used || time_after(stats->used, *used))
*used = stats->used;
*tcp_flags |= stats->tcp_flags;
ovs_stats->n_packets += stats->packet_count;
ovs_stats->n_bytes += stats->byte_count;
spin_unlock_bh(&stats->lock);
}
}
}
/* Called with ovs_mutex. */
void ovs_flow_stats_clear(struct sw_flow *flow)
{
int cpu;
/* We open code this to make sure cpu 0 is always considered */
for (cpu = 0; cpu < nr_cpu_ids; cpu = cpumask_next(cpu, &flow->cpu_used_mask)) {
struct sw_flow_stats *stats = ovsl_dereference(flow->stats[cpu]);
if (stats) {
spin_lock_bh(&stats->lock);
stats->used = 0;
stats->packet_count = 0;
stats->byte_count = 0;
stats->tcp_flags = 0;
spin_unlock_bh(&stats->lock);
}
}
}
static int check_header(struct sk_buff *skb, int len)
{
if (unlikely(skb->len < len))
return -EINVAL;
if (unlikely(!pskb_may_pull(skb, len)))
return -ENOMEM;
return 0;
}
static bool arphdr_ok(struct sk_buff *skb)
{
return pskb_may_pull(skb, skb_network_offset(skb) +
sizeof(struct arp_eth_header));
}
static int check_iphdr(struct sk_buff *skb)
{
unsigned int nh_ofs = skb_network_offset(skb);
unsigned int ip_len;
int err;
err = check_header(skb, nh_ofs + sizeof(struct iphdr));
if (unlikely(err))
return err;
ip_len = ip_hdrlen(skb);
if (unlikely(ip_len < sizeof(struct iphdr) ||
skb->len < nh_ofs + ip_len))
return -EINVAL;
skb_set_transport_header(skb, nh_ofs + ip_len);
return 0;
}
static bool tcphdr_ok(struct sk_buff *skb)
{
int th_ofs = skb_transport_offset(skb);
int tcp_len;
if (unlikely(!pskb_may_pull(skb, th_ofs + sizeof(struct tcphdr))))
return false;
tcp_len = tcp_hdrlen(skb);
if (unlikely(tcp_len < sizeof(struct tcphdr) ||
skb->len < th_ofs + tcp_len))
return false;
return true;
}
static bool udphdr_ok(struct sk_buff *skb)
{
return pskb_may_pull(skb, skb_transport_offset(skb) +
sizeof(struct udphdr));
}
static bool sctphdr_ok(struct sk_buff *skb)
{
return pskb_may_pull(skb, skb_transport_offset(skb) +
sizeof(struct sctphdr));
}
static bool icmphdr_ok(struct sk_buff *skb)
{
return pskb_may_pull(skb, skb_transport_offset(skb) +
sizeof(struct icmphdr));
}
static int parse_ipv6hdr(struct sk_buff *skb, struct sw_flow_key *key)
{
unsigned short frag_off;
unsigned int payload_ofs = 0;
unsigned int nh_ofs = skb_network_offset(skb);
unsigned int nh_len;
struct ipv6hdr *nh;
int err, nexthdr, flags = 0;
err = check_header(skb, nh_ofs + sizeof(*nh));
if (unlikely(err))
return err;
nh = ipv6_hdr(skb);
key->ip.proto = NEXTHDR_NONE;
key->ip.tos = ipv6_get_dsfield(nh);
key->ip.ttl = nh->hop_limit;
key->ipv6.label = *(__be32 *)nh & htonl(IPV6_FLOWINFO_FLOWLABEL);
key->ipv6.addr.src = nh->saddr;
key->ipv6.addr.dst = nh->daddr;
nexthdr = ipv6_find_hdr(skb, &payload_ofs, -1, &frag_off, &flags);
if (flags & IP6_FH_F_FRAG) {
if (frag_off) {
key->ip.frag = OVS_FRAG_TYPE_LATER;
key->ip.proto = nexthdr;
return 0;
}
key->ip.frag = OVS_FRAG_TYPE_FIRST;
} else {
key->ip.frag = OVS_FRAG_TYPE_NONE;
}
/* Delayed handling of error in ipv6_find_hdr() as it
* always sets flags and frag_off to a valid value which may be
* used to set key->ip.frag above.
*/
if (unlikely(nexthdr < 0))
return -EPROTO;
nh_len = payload_ofs - nh_ofs;
skb_set_transport_header(skb, nh_ofs + nh_len);
key->ip.proto = nexthdr;
return nh_len;
}
static bool icmp6hdr_ok(struct sk_buff *skb)
{
return pskb_may_pull(skb, skb_transport_offset(skb) +
sizeof(struct icmp6hdr));
}
/**
* Parse vlan tag from vlan header.
* Returns ERROR on memory error.
* Returns 0 if it encounters a non-vlan or incomplete packet.
* Returns 1 after successfully parsing vlan tag.
*/
static int parse_vlan_tag(struct sk_buff *skb, struct vlan_head *key_vh,
bool untag_vlan)
{
struct vlan_head *vh = (struct vlan_head *)skb->data;
if (likely(!eth_type_vlan(vh->tpid)))
return 0;
if (unlikely(skb->len < sizeof(struct vlan_head) + sizeof(__be16)))
return 0;
if (unlikely(!pskb_may_pull(skb, sizeof(struct vlan_head) +
sizeof(__be16))))
return -ENOMEM;
vh = (struct vlan_head *)skb->data;
key_vh->tci = vh->tci | htons(VLAN_CFI_MASK);
key_vh->tpid = vh->tpid;
if (unlikely(untag_vlan)) {
int offset = skb->data - skb_mac_header(skb);
u16 tci;
int err;
__skb_push(skb, offset);
err = __skb_vlan_pop(skb, &tci);
__skb_pull(skb, offset);
if (err)
return err;
__vlan_hwaccel_put_tag(skb, key_vh->tpid, tci);
} else {
__skb_pull(skb, sizeof(struct vlan_head));
}
return 1;
}
static void clear_vlan(struct sw_flow_key *key)
{
key->eth.vlan.tci = 0;
key->eth.vlan.tpid = 0;
key->eth.cvlan.tci = 0;
key->eth.cvlan.tpid = 0;
}
static int parse_vlan(struct sk_buff *skb, struct sw_flow_key *key)
{
int res;
if (skb_vlan_tag_present(skb)) {
key->eth.vlan.tci = htons(skb->vlan_tci) | htons(VLAN_CFI_MASK);
key->eth.vlan.tpid = skb->vlan_proto;
} else {
/* Parse outer vlan tag in the non-accelerated case. */
res = parse_vlan_tag(skb, &key->eth.vlan, true);
if (res <= 0)
return res;
}
/* Parse inner vlan tag. */
res = parse_vlan_tag(skb, &key->eth.cvlan, false);
if (res <= 0)
return res;
return 0;
}
static __be16 parse_ethertype(struct sk_buff *skb)
{
struct llc_snap_hdr {
u8 dsap; /* Always 0xAA */
u8 ssap; /* Always 0xAA */
u8 ctrl;
u8 oui[3];
__be16 ethertype;
};
struct llc_snap_hdr *llc;
__be16 proto;
proto = *(__be16 *) skb->data;
__skb_pull(skb, sizeof(__be16));
if (eth_proto_is_802_3(proto))
return proto;
if (skb->len < sizeof(struct llc_snap_hdr))
return htons(ETH_P_802_2);
if (unlikely(!pskb_may_pull(skb, sizeof(struct llc_snap_hdr))))
return htons(0);
llc = (struct llc_snap_hdr *) skb->data;
if (llc->dsap != LLC_SAP_SNAP ||
llc->ssap != LLC_SAP_SNAP ||
(llc->oui[0] | llc->oui[1] | llc->oui[2]) != 0)
return htons(ETH_P_802_2);
__skb_pull(skb, sizeof(struct llc_snap_hdr));
if (eth_proto_is_802_3(llc->ethertype))
return llc->ethertype;
return htons(ETH_P_802_2);
}
static int parse_icmpv6(struct sk_buff *skb, struct sw_flow_key *key,
int nh_len)
{
struct icmp6hdr *icmp = icmp6_hdr(skb);
/* The ICMPv6 type and code fields use the 16-bit transport port
* fields, so we need to store them in 16-bit network byte order.
*/
key->tp.src = htons(icmp->icmp6_type);
key->tp.dst = htons(icmp->icmp6_code);
memset(&key->ipv6.nd, 0, sizeof(key->ipv6.nd));
if (icmp->icmp6_code == 0 &&
(icmp->icmp6_type == NDISC_NEIGHBOUR_SOLICITATION ||
icmp->icmp6_type == NDISC_NEIGHBOUR_ADVERTISEMENT)) {
int icmp_len = skb->len - skb_transport_offset(skb);
struct nd_msg *nd;
int offset;
/* In order to process neighbor discovery options, we need the
* entire packet.
*/
if (unlikely(icmp_len < sizeof(*nd)))
return 0;
if (unlikely(skb_linearize(skb)))
return -ENOMEM;
nd = (struct nd_msg *)skb_transport_header(skb);
key->ipv6.nd.target = nd->target;
icmp_len -= sizeof(*nd);
offset = 0;
while (icmp_len >= 8) {
struct nd_opt_hdr *nd_opt =
(struct nd_opt_hdr *)(nd->opt + offset);
int opt_len = nd_opt->nd_opt_len * 8;
if (unlikely(!opt_len || opt_len > icmp_len))
return 0;
/* Store the link layer address if the appropriate
* option is provided. It is considered an error if
* the same link layer option is specified twice.
*/
if (nd_opt->nd_opt_type == ND_OPT_SOURCE_LL_ADDR
&& opt_len == 8) {
if (unlikely(!is_zero_ether_addr(key->ipv6.nd.sll)))
goto invalid;
ether_addr_copy(key->ipv6.nd.sll,
&nd->opt[offset+sizeof(*nd_opt)]);
} else if (nd_opt->nd_opt_type == ND_OPT_TARGET_LL_ADDR
&& opt_len == 8) {
if (unlikely(!is_zero_ether_addr(key->ipv6.nd.tll)))
goto invalid;
ether_addr_copy(key->ipv6.nd.tll,
&nd->opt[offset+sizeof(*nd_opt)]);
}
icmp_len -= opt_len;
offset += opt_len;
}
}
return 0;
invalid:
memset(&key->ipv6.nd.target, 0, sizeof(key->ipv6.nd.target));
memset(key->ipv6.nd.sll, 0, sizeof(key->ipv6.nd.sll));
memset(key->ipv6.nd.tll, 0, sizeof(key->ipv6.nd.tll));
return 0;
}
static int parse_nsh(struct sk_buff *skb, struct sw_flow_key *key)
{
struct nshhdr *nh;
unsigned int nh_ofs = skb_network_offset(skb);
u8 version, length;
int err;
err = check_header(skb, nh_ofs + NSH_BASE_HDR_LEN);
if (unlikely(err))
return err;
nh = nsh_hdr(skb);
version = nsh_get_ver(nh);
length = nsh_hdr_len(nh);
if (version != 0)
return -EINVAL;
err = check_header(skb, nh_ofs + length);
if (unlikely(err))
return err;
nh = nsh_hdr(skb);
key->nsh.base.flags = nsh_get_flags(nh);
key->nsh.base.ttl = nsh_get_ttl(nh);
key->nsh.base.mdtype = nh->mdtype;
key->nsh.base.np = nh->np;
key->nsh.base.path_hdr = nh->path_hdr;
switch (key->nsh.base.mdtype) {
case NSH_M_TYPE1:
if (length != NSH_M_TYPE1_LEN)
return -EINVAL;
memcpy(key->nsh.context, nh->md1.context,
sizeof(nh->md1));
break;
case NSH_M_TYPE2:
memset(key->nsh.context, 0,
sizeof(nh->md1));
break;
default:
return -EINVAL;
}
return 0;
}
/**
* key_extract_l3l4 - extracts L3/L4 header information.
* @skb: sk_buff that contains the frame, with skb->data pointing to the
* L3 header
* @key: output flow key
*
*/
static int key_extract_l3l4(struct sk_buff *skb, struct sw_flow_key *key)
{
int error;
/* Network layer. */
if (key->eth.type == htons(ETH_P_IP)) {
struct iphdr *nh;
__be16 offset;
error = check_iphdr(skb);
if (unlikely(error)) {
memset(&key->ip, 0, sizeof(key->ip));
memset(&key->ipv4, 0, sizeof(key->ipv4));
if (error == -EINVAL) {
skb->transport_header = skb->network_header;
error = 0;
}
return error;
}
nh = ip_hdr(skb);
key->ipv4.addr.src = nh->saddr;
key->ipv4.addr.dst = nh->daddr;
key->ip.proto = nh->protocol;
key->ip.tos = nh->tos;
key->ip.ttl = nh->ttl;
offset = nh->frag_off & htons(IP_OFFSET);
if (offset) {
key->ip.frag = OVS_FRAG_TYPE_LATER;
memset(&key->tp, 0, sizeof(key->tp));
return 0;
}
if (nh->frag_off & htons(IP_MF) ||
skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
key->ip.frag = OVS_FRAG_TYPE_FIRST;
else
key->ip.frag = OVS_FRAG_TYPE_NONE;
/* Transport layer. */
if (key->ip.proto == IPPROTO_TCP) {
if (tcphdr_ok(skb)) {
struct tcphdr *tcp = tcp_hdr(skb);
key->tp.src = tcp->source;
key->tp.dst = tcp->dest;
key->tp.flags = TCP_FLAGS_BE16(tcp);
} else {
memset(&key->tp, 0, sizeof(key->tp));
}
} else if (key->ip.proto == IPPROTO_UDP) {
if (udphdr_ok(skb)) {
struct udphdr *udp = udp_hdr(skb);
key->tp.src = udp->source;
key->tp.dst = udp->dest;
} else {
memset(&key->tp, 0, sizeof(key->tp));
}
} else if (key->ip.proto == IPPROTO_SCTP) {
if (sctphdr_ok(skb)) {
struct sctphdr *sctp = sctp_hdr(skb);
key->tp.src = sctp->source;
key->tp.dst = sctp->dest;
} else {
memset(&key->tp, 0, sizeof(key->tp));
}
} else if (key->ip.proto == IPPROTO_ICMP) {
if (icmphdr_ok(skb)) {
struct icmphdr *icmp = icmp_hdr(skb);
/* The ICMP type and code fields use the 16-bit
* transport port fields, so we need to store
* them in 16-bit network byte order. */
key->tp.src = htons(icmp->type);
key->tp.dst = htons(icmp->code);
} else {
memset(&key->tp, 0, sizeof(key->tp));
}
}
} else if (key->eth.type == htons(ETH_P_ARP) ||
key->eth.type == htons(ETH_P_RARP)) {
struct arp_eth_header *arp;
bool arp_available = arphdr_ok(skb);
arp = (struct arp_eth_header *)skb_network_header(skb);
if (arp_available &&
arp->ar_hrd == htons(ARPHRD_ETHER) &&
arp->ar_pro == htons(ETH_P_IP) &&
arp->ar_hln == ETH_ALEN &&
arp->ar_pln == 4) {
/* We only match on the lower 8 bits of the opcode. */
if (ntohs(arp->ar_op) <= 0xff)
key->ip.proto = ntohs(arp->ar_op);
else
key->ip.proto = 0;
memcpy(&key->ipv4.addr.src, arp->ar_sip, sizeof(key->ipv4.addr.src));
memcpy(&key->ipv4.addr.dst, arp->ar_tip, sizeof(key->ipv4.addr.dst));
ether_addr_copy(key->ipv4.arp.sha, arp->ar_sha);
ether_addr_copy(key->ipv4.arp.tha, arp->ar_tha);
} else {
memset(&key->ip, 0, sizeof(key->ip));
memset(&key->ipv4, 0, sizeof(key->ipv4));
}
} else if (eth_p_mpls(key->eth.type)) {
size_t stack_len = MPLS_HLEN;
skb_set_inner_network_header(skb, skb->mac_len);
while (1) {
__be32 lse;
error = check_header(skb, skb->mac_len + stack_len);
if (unlikely(error))
return 0;
memcpy(&lse, skb_inner_network_header(skb), MPLS_HLEN);
if (stack_len == MPLS_HLEN)
memcpy(&key->mpls.top_lse, &lse, MPLS_HLEN);
skb_set_inner_network_header(skb, skb->mac_len + stack_len);
if (lse & htonl(MPLS_LS_S_MASK))
break;
stack_len += MPLS_HLEN;
}
} else if (key->eth.type == htons(ETH_P_IPV6)) {
int nh_len; /* IPv6 Header + Extensions */
nh_len = parse_ipv6hdr(skb, key);
if (unlikely(nh_len < 0)) {
switch (nh_len) {
case -EINVAL:
memset(&key->ip, 0, sizeof(key->ip));
memset(&key->ipv6.addr, 0, sizeof(key->ipv6.addr));
/* fall-through */
case -EPROTO:
skb->transport_header = skb->network_header;
error = 0;
break;
default:
error = nh_len;
}
return error;
}
if (key->ip.frag == OVS_FRAG_TYPE_LATER) {
memset(&key->tp, 0, sizeof(key->tp));
return 0;
}
if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
key->ip.frag = OVS_FRAG_TYPE_FIRST;
/* Transport layer. */
if (key->ip.proto == NEXTHDR_TCP) {
if (tcphdr_ok(skb)) {
struct tcphdr *tcp = tcp_hdr(skb);
key->tp.src = tcp->source;
key->tp.dst = tcp->dest;
key->tp.flags = TCP_FLAGS_BE16(tcp);
} else {
memset(&key->tp, 0, sizeof(key->tp));
}
} else if (key->ip.proto == NEXTHDR_UDP) {
if (udphdr_ok(skb)) {
struct udphdr *udp = udp_hdr(skb);
key->tp.src = udp->source;
key->tp.dst = udp->dest;
} else {
memset(&key->tp, 0, sizeof(key->tp));
}
} else if (key->ip.proto == NEXTHDR_SCTP) {
if (sctphdr_ok(skb)) {
struct sctphdr *sctp = sctp_hdr(skb);
key->tp.src = sctp->source;
key->tp.dst = sctp->dest;
} else {
memset(&key->tp, 0, sizeof(key->tp));
}
} else if (key->ip.proto == NEXTHDR_ICMP) {
if (icmp6hdr_ok(skb)) {
error = parse_icmpv6(skb, key, nh_len);
if (error)
return error;
} else {
memset(&key->tp, 0, sizeof(key->tp));
}
}
} else if (key->eth.type == htons(ETH_P_NSH)) {
error = parse_nsh(skb, key);
if (error)
return error;
}
return 0;
}
/**
* key_extract - extracts a flow key from an Ethernet frame.
* @skb: sk_buff that contains the frame, with skb->data pointing to the
* Ethernet header
* @key: output flow key
*
* The caller must ensure that skb->len >= ETH_HLEN.
*
* Returns 0 if successful, otherwise a negative errno value.
*
* Initializes @skb header fields as follows:
*
* - skb->mac_header: the L2 header.
*
* - skb->network_header: just past the L2 header, or just past the
* VLAN header, to the first byte of the L2 payload.
*
* - skb->transport_header: If key->eth.type is ETH_P_IP or ETH_P_IPV6
* on output, then just past the IP header, if one is present and
* of a correct length, otherwise the same as skb->network_header.
* For other key->eth.type values it is left untouched.
*
* - skb->protocol: the type of the data starting at skb->network_header.
* Equals to key->eth.type.
*/
static int key_extract(struct sk_buff *skb, struct sw_flow_key *key)
{
struct ethhdr *eth;
/* Flags are always used as part of stats */
key->tp.flags = 0;
skb_reset_mac_header(skb);
/* Link layer. */
clear_vlan(key);
if (ovs_key_mac_proto(key) == MAC_PROTO_NONE) {
if (unlikely(eth_type_vlan(skb->protocol)))
return -EINVAL;
skb_reset_network_header(skb);
key->eth.type = skb->protocol;
} else {
eth = eth_hdr(skb);
ether_addr_copy(key->eth.src, eth->h_source);
ether_addr_copy(key->eth.dst, eth->h_dest);
__skb_pull(skb, 2 * ETH_ALEN);
/* We are going to push all headers that we pull, so no need to
* update skb->csum here.
*/
if (unlikely(parse_vlan(skb, key)))
return -ENOMEM;
key->eth.type = parse_ethertype(skb);
if (unlikely(key->eth.type == htons(0)))
return -ENOMEM;
/* Multiple tagged packets need to retain TPID to satisfy
* skb_vlan_pop(), which will later shift the ethertype into
* skb->protocol.
*/
if (key->eth.cvlan.tci & htons(VLAN_CFI_MASK))
skb->protocol = key->eth.cvlan.tpid;
else
skb->protocol = key->eth.type;
skb_reset_network_header(skb);
__skb_push(skb, skb->data - skb_mac_header(skb));
}
skb_reset_mac_len(skb);
/* Fill out L3/L4 key info, if any */
return key_extract_l3l4(skb, key);
}
/* In the case of conntrack fragment handling it expects L3 headers,
* add a helper.
*/
int ovs_flow_key_update_l3l4(struct sk_buff *skb, struct sw_flow_key *key)
{
return key_extract_l3l4(skb, key);
}
int ovs_flow_key_update(struct sk_buff *skb, struct sw_flow_key *key)
{
int res;
res = key_extract(skb, key);
if (!res)
key->mac_proto &= ~SW_FLOW_KEY_INVALID;
return res;
}
static int key_extract_mac_proto(struct sk_buff *skb)
{
switch (skb->dev->type) {
case ARPHRD_ETHER:
return MAC_PROTO_ETHERNET;
case ARPHRD_NONE:
if (skb->protocol == htons(ETH_P_TEB))
return MAC_PROTO_ETHERNET;
return MAC_PROTO_NONE;
}
WARN_ON_ONCE(1);
return -EINVAL;
}
int ovs_flow_key_extract(const struct ip_tunnel_info *tun_info,
struct sk_buff *skb, struct sw_flow_key *key)
{
#if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
struct tc_skb_ext *tc_ext;
#endif
int res, err;
/* Extract metadata from packet. */
if (tun_info) {
key->tun_proto = ip_tunnel_info_af(tun_info);
memcpy(&key->tun_key, &tun_info->key, sizeof(key->tun_key));
if (tun_info->options_len) {
BUILD_BUG_ON((1 << (sizeof(tun_info->options_len) *
8)) - 1
> sizeof(key->tun_opts));
ip_tunnel_info_opts_get(TUN_METADATA_OPTS(key, tun_info->options_len),
tun_info);
key->tun_opts_len = tun_info->options_len;
} else {
key->tun_opts_len = 0;
}
} else {
key->tun_proto = 0;
key->tun_opts_len = 0;
memset(&key->tun_key, 0, sizeof(key->tun_key));
}
key->phy.priority = skb->priority;
key->phy.in_port = OVS_CB(skb)->input_vport->port_no;
key->phy.skb_mark = skb->mark;
key->ovs_flow_hash = 0;
res = key_extract_mac_proto(skb);
if (res < 0)
return res;
key->mac_proto = res;
#if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
if (static_branch_unlikely(&tc_recirc_sharing_support)) {
tc_ext = skb_ext_find(skb, TC_SKB_EXT);
key->recirc_id = tc_ext ? tc_ext->chain : 0;
} else {
key->recirc_id = 0;
}
#else
key->recirc_id = 0;
#endif
err = key_extract(skb, key);
if (!err)
ovs_ct_fill_key(skb, key); /* Must be after key_extract(). */
return err;
}
int ovs_flow_key_extract_userspace(struct net *net, const struct nlattr *attr,
struct sk_buff *skb,
struct sw_flow_key *key, bool log)
{
const struct nlattr *a[OVS_KEY_ATTR_MAX + 1];
u64 attrs = 0;
int err;
err = parse_flow_nlattrs(attr, a, &attrs, log);
if (err)
return -EINVAL;
/* Extract metadata from netlink attributes. */
err = ovs_nla_get_flow_metadata(net, a, attrs, key, log);
if (err)
return err;
/* key_extract assumes that skb->protocol is set-up for
* layer 3 packets which is the case for other callers,
* in particular packets received from the network stack.
* Here the correct value can be set from the metadata
* extracted above.
* For L2 packet key eth type would be zero. skb protocol
* would be set to correct value later during key-extact.
*/
skb->protocol = key->eth.type;
err = key_extract(skb, key);
if (err)
return err;
/* Check that we have conntrack original direction tuple metadata only
* for packets for which it makes sense. Otherwise the key may be
* corrupted due to overlapping key fields.
*/
if (attrs & (1 << OVS_KEY_ATTR_CT_ORIG_TUPLE_IPV4) &&
key->eth.type != htons(ETH_P_IP))
return -EINVAL;
if (attrs & (1 << OVS_KEY_ATTR_CT_ORIG_TUPLE_IPV6) &&
(key->eth.type != htons(ETH_P_IPV6) ||
sw_flow_key_is_nd(key)))
return -EINVAL;
return 0;
}
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