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seg6_local.c
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* SR-IPv6 implementation
*
* Authors:
* David Lebrun <[email protected]>
* eBPF support: Mathieu Xhonneux <[email protected]>
*/
#include <linux/filter.h>
#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/net.h>
#include <linux/module.h>
#include <net/ip.h>
#include <net/lwtunnel.h>
#include <net/netevent.h>
#include <net/netns/generic.h>
#include <net/ip6_fib.h>
#include <net/route.h>
#include <net/seg6.h>
#include <linux/seg6.h>
#include <linux/seg6_local.h>
#include <net/addrconf.h>
#include <net/ip6_route.h>
#include <net/dst_cache.h>
#include <net/ip_tunnels.h>
#ifdef CONFIG_IPV6_SEG6_HMAC
#include <net/seg6_hmac.h>
#endif
#include <net/seg6_local.h>
#include <linux/etherdevice.h>
#include <linux/bpf.h>
#include <linux/netfilter.h>
#define SEG6_F_ATTR(i) BIT(i)
struct seg6_local_lwt;
/* callbacks used for customizing the creation and destruction of a behavior */
struct seg6_local_lwtunnel_ops {
int (*build_state)(struct seg6_local_lwt *slwt, const void *cfg,
struct netlink_ext_ack *extack);
void (*destroy_state)(struct seg6_local_lwt *slwt);
};
struct seg6_action_desc {
int action;
unsigned long attrs;
/* The optattrs field is used for specifying all the optional
* attributes supported by a specific behavior.
* It means that if one of these attributes is not provided in the
* netlink message during the behavior creation, no errors will be
* returned to the userspace.
*
* Each attribute can be only of two types (mutually exclusive):
* 1) required or 2) optional.
* Every user MUST obey to this rule! If you set an attribute as
* required the same attribute CANNOT be set as optional and vice
* versa.
*/
unsigned long optattrs;
int (*input)(struct sk_buff *skb, struct seg6_local_lwt *slwt);
int static_headroom;
struct seg6_local_lwtunnel_ops slwt_ops;
};
struct bpf_lwt_prog {
struct bpf_prog *prog;
char *name;
};
enum seg6_end_dt_mode {
DT_INVALID_MODE = -EINVAL,
DT_LEGACY_MODE = 0,
DT_VRF_MODE = 1,
};
struct seg6_end_dt_info {
enum seg6_end_dt_mode mode;
struct net *net;
/* VRF device associated to the routing table used by the SRv6
* End.DT4/DT6 behavior for routing IPv4/IPv6 packets.
*/
int vrf_ifindex;
int vrf_table;
/* tunneled packet family (IPv4 or IPv6).
* Protocol and header length are inferred from family.
*/
u16 family;
};
struct pcpu_seg6_local_counters {
u64_stats_t packets;
u64_stats_t bytes;
u64_stats_t errors;
struct u64_stats_sync syncp;
};
/* This struct groups all the SRv6 Behavior counters supported so far.
*
* put_nla_counters() makes use of this data structure to collect all counter
* values after the per-CPU counter evaluation has been performed.
* Finally, each counter value (in seg6_local_counters) is stored in the
* corresponding netlink attribute and sent to user space.
*
* NB: we don't want to expose this structure to user space!
*/
struct seg6_local_counters {
__u64 packets;
__u64 bytes;
__u64 errors;
};
#define seg6_local_alloc_pcpu_counters(__gfp) \
__netdev_alloc_pcpu_stats(struct pcpu_seg6_local_counters, \
((__gfp) | __GFP_ZERO))
#define SEG6_F_LOCAL_COUNTERS SEG6_F_ATTR(SEG6_LOCAL_COUNTERS)
struct seg6_local_lwt {
int action;
struct ipv6_sr_hdr *srh;
int table;
struct in_addr nh4;
struct in6_addr nh6;
int iif;
int oif;
struct bpf_lwt_prog bpf;
#ifdef CONFIG_NET_L3_MASTER_DEV
struct seg6_end_dt_info dt_info;
#endif
struct pcpu_seg6_local_counters __percpu *pcpu_counters;
int headroom;
struct seg6_action_desc *desc;
/* unlike the required attrs, we have to track the optional attributes
* that have been effectively parsed.
*/
unsigned long parsed_optattrs;
};
static struct seg6_local_lwt *seg6_local_lwtunnel(struct lwtunnel_state *lwt)
{
return (struct seg6_local_lwt *)lwt->data;
}
static struct ipv6_sr_hdr *get_and_validate_srh(struct sk_buff *skb)
{
struct ipv6_sr_hdr *srh;
srh = seg6_get_srh(skb, IP6_FH_F_SKIP_RH);
if (!srh)
return NULL;
#ifdef CONFIG_IPV6_SEG6_HMAC
if (!seg6_hmac_validate_skb(skb))
return NULL;
#endif
return srh;
}
static bool decap_and_validate(struct sk_buff *skb, int proto)
{
struct ipv6_sr_hdr *srh;
unsigned int off = 0;
srh = seg6_get_srh(skb, 0);
if (srh && srh->segments_left > 0)
return false;
#ifdef CONFIG_IPV6_SEG6_HMAC
if (srh && !seg6_hmac_validate_skb(skb))
return false;
#endif
if (ipv6_find_hdr(skb, &off, proto, NULL, NULL) < 0)
return false;
if (!pskb_pull(skb, off))
return false;
skb_postpull_rcsum(skb, skb_network_header(skb), off);
skb_reset_network_header(skb);
skb_reset_transport_header(skb);
if (iptunnel_pull_offloads(skb))
return false;
return true;
}
static void advance_nextseg(struct ipv6_sr_hdr *srh, struct in6_addr *daddr)
{
struct in6_addr *addr;
srh->segments_left--;
addr = srh->segments + srh->segments_left;
*daddr = *addr;
}
static int
seg6_lookup_any_nexthop(struct sk_buff *skb, struct in6_addr *nhaddr,
u32 tbl_id, bool local_delivery)
{
struct net *net = dev_net(skb->dev);
struct ipv6hdr *hdr = ipv6_hdr(skb);
int flags = RT6_LOOKUP_F_HAS_SADDR;
struct dst_entry *dst = NULL;
struct rt6_info *rt;
struct flowi6 fl6;
int dev_flags = 0;
memset(&fl6, 0, sizeof(fl6));
fl6.flowi6_iif = skb->dev->ifindex;
fl6.daddr = nhaddr ? *nhaddr : hdr->daddr;
fl6.saddr = hdr->saddr;
fl6.flowlabel = ip6_flowinfo(hdr);
fl6.flowi6_mark = skb->mark;
fl6.flowi6_proto = hdr->nexthdr;
if (nhaddr)
fl6.flowi6_flags = FLOWI_FLAG_KNOWN_NH;
if (!tbl_id) {
dst = ip6_route_input_lookup(net, skb->dev, &fl6, skb, flags);
} else {
struct fib6_table *table;
table = fib6_get_table(net, tbl_id);
if (!table)
goto out;
rt = ip6_pol_route(net, table, 0, &fl6, skb, flags);
dst = &rt->dst;
}
/* we want to discard traffic destined for local packet processing,
* if @local_delivery is set to false.
*/
if (!local_delivery)
dev_flags |= IFF_LOOPBACK;
if (dst && (dst->dev->flags & dev_flags) && !dst->error) {
dst_release(dst);
dst = NULL;
}
out:
if (!dst) {
rt = net->ipv6.ip6_blk_hole_entry;
dst = &rt->dst;
dst_hold(dst);
}
skb_dst_drop(skb);
skb_dst_set(skb, dst);
return dst->error;
}
int seg6_lookup_nexthop(struct sk_buff *skb,
struct in6_addr *nhaddr, u32 tbl_id)
{
return seg6_lookup_any_nexthop(skb, nhaddr, tbl_id, false);
}
/* regular endpoint function */
static int input_action_end(struct sk_buff *skb, struct seg6_local_lwt *slwt)
{
struct ipv6_sr_hdr *srh;
srh = get_and_validate_srh(skb);
if (!srh)
goto drop;
advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
seg6_lookup_nexthop(skb, NULL, 0);
return dst_input(skb);
drop:
kfree_skb(skb);
return -EINVAL;
}
/* regular endpoint, and forward to specified nexthop */
static int input_action_end_x(struct sk_buff *skb, struct seg6_local_lwt *slwt)
{
struct ipv6_sr_hdr *srh;
srh = get_and_validate_srh(skb);
if (!srh)
goto drop;
advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
seg6_lookup_nexthop(skb, &slwt->nh6, 0);
return dst_input(skb);
drop:
kfree_skb(skb);
return -EINVAL;
}
static int input_action_end_t(struct sk_buff *skb, struct seg6_local_lwt *slwt)
{
struct ipv6_sr_hdr *srh;
srh = get_and_validate_srh(skb);
if (!srh)
goto drop;
advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
seg6_lookup_nexthop(skb, NULL, slwt->table);
return dst_input(skb);
drop:
kfree_skb(skb);
return -EINVAL;
}
/* decapsulate and forward inner L2 frame on specified interface */
static int input_action_end_dx2(struct sk_buff *skb,
struct seg6_local_lwt *slwt)
{
struct net *net = dev_net(skb->dev);
struct net_device *odev;
struct ethhdr *eth;
if (!decap_and_validate(skb, IPPROTO_ETHERNET))
goto drop;
if (!pskb_may_pull(skb, ETH_HLEN))
goto drop;
skb_reset_mac_header(skb);
eth = (struct ethhdr *)skb->data;
/* To determine the frame's protocol, we assume it is 802.3. This avoids
* a call to eth_type_trans(), which is not really relevant for our
* use case.
*/
if (!eth_proto_is_802_3(eth->h_proto))
goto drop;
odev = dev_get_by_index_rcu(net, slwt->oif);
if (!odev)
goto drop;
/* As we accept Ethernet frames, make sure the egress device is of
* the correct type.
*/
if (odev->type != ARPHRD_ETHER)
goto drop;
if (!(odev->flags & IFF_UP) || !netif_carrier_ok(odev))
goto drop;
skb_orphan(skb);
if (skb_warn_if_lro(skb))
goto drop;
skb_forward_csum(skb);
if (skb->len - ETH_HLEN > odev->mtu)
goto drop;
skb->dev = odev;
skb->protocol = eth->h_proto;
return dev_queue_xmit(skb);
drop:
kfree_skb(skb);
return -EINVAL;
}
static int input_action_end_dx6_finish(struct net *net, struct sock *sk,
struct sk_buff *skb)
{
struct dst_entry *orig_dst = skb_dst(skb);
struct in6_addr *nhaddr = NULL;
struct seg6_local_lwt *slwt;
slwt = seg6_local_lwtunnel(orig_dst->lwtstate);
/* The inner packet is not associated to any local interface,
* so we do not call netif_rx().
*
* If slwt->nh6 is set to ::, then lookup the nexthop for the
* inner packet's DA. Otherwise, use the specified nexthop.
*/
if (!ipv6_addr_any(&slwt->nh6))
nhaddr = &slwt->nh6;
seg6_lookup_nexthop(skb, nhaddr, 0);
return dst_input(skb);
}
/* decapsulate and forward to specified nexthop */
static int input_action_end_dx6(struct sk_buff *skb,
struct seg6_local_lwt *slwt)
{
/* this function accepts IPv6 encapsulated packets, with either
* an SRH with SL=0, or no SRH.
*/
if (!decap_and_validate(skb, IPPROTO_IPV6))
goto drop;
if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
goto drop;
skb_set_transport_header(skb, sizeof(struct ipv6hdr));
nf_reset_ct(skb);
if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
dev_net(skb->dev), NULL, skb, NULL,
skb_dst(skb)->dev, input_action_end_dx6_finish);
return input_action_end_dx6_finish(dev_net(skb->dev), NULL, skb);
drop:
kfree_skb(skb);
return -EINVAL;
}
static int input_action_end_dx4_finish(struct net *net, struct sock *sk,
struct sk_buff *skb)
{
struct dst_entry *orig_dst = skb_dst(skb);
struct seg6_local_lwt *slwt;
struct iphdr *iph;
__be32 nhaddr;
int err;
slwt = seg6_local_lwtunnel(orig_dst->lwtstate);
iph = ip_hdr(skb);
nhaddr = slwt->nh4.s_addr ?: iph->daddr;
skb_dst_drop(skb);
err = ip_route_input(skb, nhaddr, iph->saddr, 0, skb->dev);
if (err) {
kfree_skb(skb);
return -EINVAL;
}
return dst_input(skb);
}
static int input_action_end_dx4(struct sk_buff *skb,
struct seg6_local_lwt *slwt)
{
if (!decap_and_validate(skb, IPPROTO_IPIP))
goto drop;
if (!pskb_may_pull(skb, sizeof(struct iphdr)))
goto drop;
skb->protocol = htons(ETH_P_IP);
skb_set_transport_header(skb, sizeof(struct iphdr));
nf_reset_ct(skb);
if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
return NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING,
dev_net(skb->dev), NULL, skb, NULL,
skb_dst(skb)->dev, input_action_end_dx4_finish);
return input_action_end_dx4_finish(dev_net(skb->dev), NULL, skb);
drop:
kfree_skb(skb);
return -EINVAL;
}
#ifdef CONFIG_NET_L3_MASTER_DEV
static struct net *fib6_config_get_net(const struct fib6_config *fib6_cfg)
{
const struct nl_info *nli = &fib6_cfg->fc_nlinfo;
return nli->nl_net;
}
static int __seg6_end_dt_vrf_build(struct seg6_local_lwt *slwt, const void *cfg,
u16 family, struct netlink_ext_ack *extack)
{
struct seg6_end_dt_info *info = &slwt->dt_info;
int vrf_ifindex;
struct net *net;
net = fib6_config_get_net(cfg);
/* note that vrf_table was already set by parse_nla_vrftable() */
vrf_ifindex = l3mdev_ifindex_lookup_by_table_id(L3MDEV_TYPE_VRF, net,
info->vrf_table);
if (vrf_ifindex < 0) {
if (vrf_ifindex == -EPERM) {
NL_SET_ERR_MSG(extack,
"Strict mode for VRF is disabled");
} else if (vrf_ifindex == -ENODEV) {
NL_SET_ERR_MSG(extack,
"Table has no associated VRF device");
} else {
pr_debug("seg6local: SRv6 End.DT* creation error=%d\n",
vrf_ifindex);
}
return vrf_ifindex;
}
info->net = net;
info->vrf_ifindex = vrf_ifindex;
info->family = family;
info->mode = DT_VRF_MODE;
return 0;
}
/* The SRv6 End.DT4/DT6 behavior extracts the inner (IPv4/IPv6) packet and
* routes the IPv4/IPv6 packet by looking at the configured routing table.
*
* In the SRv6 End.DT4/DT6 use case, we can receive traffic (IPv6+Segment
* Routing Header packets) from several interfaces and the outer IPv6
* destination address (DA) is used for retrieving the specific instance of the
* End.DT4/DT6 behavior that should process the packets.
*
* However, the inner IPv4/IPv6 packet is not really bound to any receiving
* interface and thus the End.DT4/DT6 sets the VRF (associated with the
* corresponding routing table) as the *receiving* interface.
* In other words, the End.DT4/DT6 processes a packet as if it has been received
* directly by the VRF (and not by one of its slave devices, if any).
* In this way, the VRF interface is used for routing the IPv4/IPv6 packet in
* according to the routing table configured by the End.DT4/DT6 instance.
*
* This design allows you to get some interesting features like:
* 1) the statistics on rx packets;
* 2) the possibility to install a packet sniffer on the receiving interface
* (the VRF one) for looking at the incoming packets;
* 3) the possibility to leverage the netfilter prerouting hook for the inner
* IPv4 packet.
*
* This function returns:
* - the sk_buff* when the VRF rcv handler has processed the packet correctly;
* - NULL when the skb is consumed by the VRF rcv handler;
* - a pointer which encodes a negative error number in case of error.
* Note that in this case, the function takes care of freeing the skb.
*/
static struct sk_buff *end_dt_vrf_rcv(struct sk_buff *skb, u16 family,
struct net_device *dev)
{
/* based on l3mdev_ip_rcv; we are only interested in the master */
if (unlikely(!netif_is_l3_master(dev) && !netif_has_l3_rx_handler(dev)))
goto drop;
if (unlikely(!dev->l3mdev_ops->l3mdev_l3_rcv))
goto drop;
/* the decap packet IPv4/IPv6 does not come with any mac header info.
* We must unset the mac header to allow the VRF device to rebuild it,
* just in case there is a sniffer attached on the device.
*/
skb_unset_mac_header(skb);
skb = dev->l3mdev_ops->l3mdev_l3_rcv(dev, skb, family);
if (!skb)
/* the skb buffer was consumed by the handler */
return NULL;
/* when a packet is received by a VRF or by one of its slaves, the
* master device reference is set into the skb.
*/
if (unlikely(skb->dev != dev || skb->skb_iif != dev->ifindex))
goto drop;
return skb;
drop:
kfree_skb(skb);
return ERR_PTR(-EINVAL);
}
static struct net_device *end_dt_get_vrf_rcu(struct sk_buff *skb,
struct seg6_end_dt_info *info)
{
int vrf_ifindex = info->vrf_ifindex;
struct net *net = info->net;
if (unlikely(vrf_ifindex < 0))
goto error;
if (unlikely(!net_eq(dev_net(skb->dev), net)))
goto error;
return dev_get_by_index_rcu(net, vrf_ifindex);
error:
return NULL;
}
static struct sk_buff *end_dt_vrf_core(struct sk_buff *skb,
struct seg6_local_lwt *slwt, u16 family)
{
struct seg6_end_dt_info *info = &slwt->dt_info;
struct net_device *vrf;
__be16 protocol;
int hdrlen;
vrf = end_dt_get_vrf_rcu(skb, info);
if (unlikely(!vrf))
goto drop;
switch (family) {
case AF_INET:
protocol = htons(ETH_P_IP);
hdrlen = sizeof(struct iphdr);
break;
case AF_INET6:
protocol = htons(ETH_P_IPV6);
hdrlen = sizeof(struct ipv6hdr);
break;
case AF_UNSPEC:
fallthrough;
default:
goto drop;
}
if (unlikely(info->family != AF_UNSPEC && info->family != family)) {
pr_warn_once("seg6local: SRv6 End.DT* family mismatch");
goto drop;
}
skb->protocol = protocol;
skb_dst_drop(skb);
skb_set_transport_header(skb, hdrlen);
nf_reset_ct(skb);
return end_dt_vrf_rcv(skb, family, vrf);
drop:
kfree_skb(skb);
return ERR_PTR(-EINVAL);
}
static int input_action_end_dt4(struct sk_buff *skb,
struct seg6_local_lwt *slwt)
{
struct iphdr *iph;
int err;
if (!decap_and_validate(skb, IPPROTO_IPIP))
goto drop;
if (!pskb_may_pull(skb, sizeof(struct iphdr)))
goto drop;
skb = end_dt_vrf_core(skb, slwt, AF_INET);
if (!skb)
/* packet has been processed and consumed by the VRF */
return 0;
if (IS_ERR(skb))
return PTR_ERR(skb);
iph = ip_hdr(skb);
err = ip_route_input(skb, iph->daddr, iph->saddr, 0, skb->dev);
if (unlikely(err))
goto drop;
return dst_input(skb);
drop:
kfree_skb(skb);
return -EINVAL;
}
static int seg6_end_dt4_build(struct seg6_local_lwt *slwt, const void *cfg,
struct netlink_ext_ack *extack)
{
return __seg6_end_dt_vrf_build(slwt, cfg, AF_INET, extack);
}
static enum
seg6_end_dt_mode seg6_end_dt6_parse_mode(struct seg6_local_lwt *slwt)
{
unsigned long parsed_optattrs = slwt->parsed_optattrs;
bool legacy, vrfmode;
legacy = !!(parsed_optattrs & SEG6_F_ATTR(SEG6_LOCAL_TABLE));
vrfmode = !!(parsed_optattrs & SEG6_F_ATTR(SEG6_LOCAL_VRFTABLE));
if (!(legacy ^ vrfmode))
/* both are absent or present: invalid DT6 mode */
return DT_INVALID_MODE;
return legacy ? DT_LEGACY_MODE : DT_VRF_MODE;
}
static enum seg6_end_dt_mode seg6_end_dt6_get_mode(struct seg6_local_lwt *slwt)
{
struct seg6_end_dt_info *info = &slwt->dt_info;
return info->mode;
}
static int seg6_end_dt6_build(struct seg6_local_lwt *slwt, const void *cfg,
struct netlink_ext_ack *extack)
{
enum seg6_end_dt_mode mode = seg6_end_dt6_parse_mode(slwt);
struct seg6_end_dt_info *info = &slwt->dt_info;
switch (mode) {
case DT_LEGACY_MODE:
info->mode = DT_LEGACY_MODE;
return 0;
case DT_VRF_MODE:
return __seg6_end_dt_vrf_build(slwt, cfg, AF_INET6, extack);
default:
NL_SET_ERR_MSG(extack, "table or vrftable must be specified");
return -EINVAL;
}
}
#endif
static int input_action_end_dt6(struct sk_buff *skb,
struct seg6_local_lwt *slwt)
{
if (!decap_and_validate(skb, IPPROTO_IPV6))
goto drop;
if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
goto drop;
#ifdef CONFIG_NET_L3_MASTER_DEV
if (seg6_end_dt6_get_mode(slwt) == DT_LEGACY_MODE)
goto legacy_mode;
/* DT6_VRF_MODE */
skb = end_dt_vrf_core(skb, slwt, AF_INET6);
if (!skb)
/* packet has been processed and consumed by the VRF */
return 0;
if (IS_ERR(skb))
return PTR_ERR(skb);
/* note: this time we do not need to specify the table because the VRF
* takes care of selecting the correct table.
*/
seg6_lookup_any_nexthop(skb, NULL, 0, true);
return dst_input(skb);
legacy_mode:
#endif
skb_set_transport_header(skb, sizeof(struct ipv6hdr));
seg6_lookup_any_nexthop(skb, NULL, slwt->table, true);
return dst_input(skb);
drop:
kfree_skb(skb);
return -EINVAL;
}
#ifdef CONFIG_NET_L3_MASTER_DEV
static int seg6_end_dt46_build(struct seg6_local_lwt *slwt, const void *cfg,
struct netlink_ext_ack *extack)
{
return __seg6_end_dt_vrf_build(slwt, cfg, AF_UNSPEC, extack);
}
static int input_action_end_dt46(struct sk_buff *skb,
struct seg6_local_lwt *slwt)
{
unsigned int off = 0;
int nexthdr;
nexthdr = ipv6_find_hdr(skb, &off, -1, NULL, NULL);
if (unlikely(nexthdr < 0))
goto drop;
switch (nexthdr) {
case IPPROTO_IPIP:
return input_action_end_dt4(skb, slwt);
case IPPROTO_IPV6:
return input_action_end_dt6(skb, slwt);
}
drop:
kfree_skb(skb);
return -EINVAL;
}
#endif
/* push an SRH on top of the current one */
static int input_action_end_b6(struct sk_buff *skb, struct seg6_local_lwt *slwt)
{
struct ipv6_sr_hdr *srh;
int err = -EINVAL;
srh = get_and_validate_srh(skb);
if (!srh)
goto drop;
err = seg6_do_srh_inline(skb, slwt->srh);
if (err)
goto drop;
skb_set_transport_header(skb, sizeof(struct ipv6hdr));
seg6_lookup_nexthop(skb, NULL, 0);
return dst_input(skb);
drop:
kfree_skb(skb);
return err;
}
/* encapsulate within an outer IPv6 header and a specified SRH */
static int input_action_end_b6_encap(struct sk_buff *skb,
struct seg6_local_lwt *slwt)
{
struct ipv6_sr_hdr *srh;
int err = -EINVAL;
srh = get_and_validate_srh(skb);
if (!srh)
goto drop;
advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
skb_reset_inner_headers(skb);
skb->encapsulation = 1;
err = seg6_do_srh_encap(skb, slwt->srh, IPPROTO_IPV6);
if (err)
goto drop;
skb_set_transport_header(skb, sizeof(struct ipv6hdr));
seg6_lookup_nexthop(skb, NULL, 0);
return dst_input(skb);
drop:
kfree_skb(skb);
return err;
}
DEFINE_PER_CPU(struct seg6_bpf_srh_state, seg6_bpf_srh_states);
bool seg6_bpf_has_valid_srh(struct sk_buff *skb)
{
struct seg6_bpf_srh_state *srh_state =
this_cpu_ptr(&seg6_bpf_srh_states);
struct ipv6_sr_hdr *srh = srh_state->srh;
if (unlikely(srh == NULL))
return false;
if (unlikely(!srh_state->valid)) {
if ((srh_state->hdrlen & 7) != 0)
return false;
srh->hdrlen = (u8)(srh_state->hdrlen >> 3);
if (!seg6_validate_srh(srh, (srh->hdrlen + 1) << 3, true))
return false;
srh_state->valid = true;
}
return true;
}
static int input_action_end_bpf(struct sk_buff *skb,
struct seg6_local_lwt *slwt)
{
struct seg6_bpf_srh_state *srh_state =
this_cpu_ptr(&seg6_bpf_srh_states);
struct ipv6_sr_hdr *srh;
int ret;
srh = get_and_validate_srh(skb);
if (!srh) {
kfree_skb(skb);
return -EINVAL;
}
advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
/* preempt_disable is needed to protect the per-CPU buffer srh_state,
* which is also accessed by the bpf_lwt_seg6_* helpers
*/
preempt_disable();
srh_state->srh = srh;
srh_state->hdrlen = srh->hdrlen << 3;
srh_state->valid = true;
rcu_read_lock();
bpf_compute_data_pointers(skb);
ret = bpf_prog_run_save_cb(slwt->bpf.prog, skb);
rcu_read_unlock();
switch (ret) {
case BPF_OK:
case BPF_REDIRECT:
break;
case BPF_DROP:
goto drop;
default:
pr_warn_once("bpf-seg6local: Illegal return value %u\n", ret);
goto drop;
}
if (srh_state->srh && !seg6_bpf_has_valid_srh(skb))
goto drop;
preempt_enable();
if (ret != BPF_REDIRECT)
seg6_lookup_nexthop(skb, NULL, 0);
return dst_input(skb);
drop:
preempt_enable();
kfree_skb(skb);
return -EINVAL;
}
static struct seg6_action_desc seg6_action_table[] = {
{
.action = SEG6_LOCAL_ACTION_END,
.attrs = 0,
.optattrs = SEG6_F_LOCAL_COUNTERS,
.input = input_action_end,
},
{
.action = SEG6_LOCAL_ACTION_END_X,
.attrs = SEG6_F_ATTR(SEG6_LOCAL_NH6),
.optattrs = SEG6_F_LOCAL_COUNTERS,
.input = input_action_end_x,
},
{
.action = SEG6_LOCAL_ACTION_END_T,
.attrs = SEG6_F_ATTR(SEG6_LOCAL_TABLE),
.optattrs = SEG6_F_LOCAL_COUNTERS,
.input = input_action_end_t,
},
{
.action = SEG6_LOCAL_ACTION_END_DX2,
.attrs = SEG6_F_ATTR(SEG6_LOCAL_OIF),
.optattrs = SEG6_F_LOCAL_COUNTERS,
.input = input_action_end_dx2,
},
{
.action = SEG6_LOCAL_ACTION_END_DX6,
.attrs = SEG6_F_ATTR(SEG6_LOCAL_NH6),
.optattrs = SEG6_F_LOCAL_COUNTERS,
.input = input_action_end_dx6,
},
{
.action = SEG6_LOCAL_ACTION_END_DX4,
.attrs = SEG6_F_ATTR(SEG6_LOCAL_NH4),
.optattrs = SEG6_F_LOCAL_COUNTERS,
.input = input_action_end_dx4,
},
{
.action = SEG6_LOCAL_ACTION_END_DT4,
.attrs = SEG6_F_ATTR(SEG6_LOCAL_VRFTABLE),
.optattrs = SEG6_F_LOCAL_COUNTERS,
#ifdef CONFIG_NET_L3_MASTER_DEV
.input = input_action_end_dt4,
.slwt_ops = {
.build_state = seg6_end_dt4_build,
},
#endif
},
{
.action = SEG6_LOCAL_ACTION_END_DT6,
#ifdef CONFIG_NET_L3_MASTER_DEV