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selftests_bpf: add L2 encap to test_tc_tunnel
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Update test_tc_tunnel to verify adding inner L2 header
encapsulation (an MPLS label or ethernet header) works.

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Alan Maguire authored and Daniel Borkmann committed Apr 11, 2019
1 parent 1db04c3 commit 3ec61df
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Showing 3 changed files with 277 additions and 59 deletions.
4 changes: 4 additions & 0 deletions tools/testing/selftests/bpf/config
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Original file line number Diff line number Diff line change
Expand Up @@ -29,3 +29,7 @@ CONFIG_NET_FOU=m
CONFIG_NET_FOU_IP_TUNNELS=y
CONFIG_IPV6_FOU=m
CONFIG_IPV6_FOU_TUNNEL=m
CONFIG_MPLS=y
CONFIG_NET_MPLS_GSO=m
CONFIG_MPLS_ROUTING=m
CONFIG_MPLS_IPTUNNEL=m
219 changes: 191 additions & 28 deletions tools/testing/selftests/bpf/progs/test_tc_tunnel.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/mpls.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/pkt_cls.h>
Expand All @@ -22,7 +23,14 @@
static const int cfg_port = 8000;

static const int cfg_udp_src = 20000;
static const int cfg_udp_dst = 5555;

#define UDP_PORT 5555
#define MPLS_OVER_UDP_PORT 6635
#define ETH_OVER_UDP_PORT 7777

/* MPLS label 1000 with S bit (last label) set and ttl of 255. */
static const __u32 mpls_label = __bpf_constant_htonl(1000 << 12 |
MPLS_LS_S_MASK | 0xff);

struct gre_hdr {
__be16 flags;
Expand All @@ -37,11 +45,13 @@ union l4hdr {
struct v4hdr {
struct iphdr ip;
union l4hdr l4hdr;
__u8 pad[16]; /* enough space for L2 header */
} __attribute__((packed));

struct v6hdr {
struct ipv6hdr ip;
union l4hdr l4hdr;
__u8 pad[16]; /* enough space for L2 header */
} __attribute__((packed));

static __always_inline void set_ipv4_csum(struct iphdr *iph)
Expand All @@ -59,13 +69,15 @@ static __always_inline void set_ipv4_csum(struct iphdr *iph)
iph->check = ~((csum & 0xffff) + (csum >> 16));
}

static __always_inline int encap_ipv4(struct __sk_buff *skb, __u8 encap_proto)
static __always_inline int encap_ipv4(struct __sk_buff *skb, __u8 encap_proto,
__u16 l2_proto)
{
__u16 udp_dst = UDP_PORT;
struct iphdr iph_inner;
struct v4hdr h_outer;
struct tcphdr tcph;
int olen, l2_len;
__u64 flags;
int olen;

if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_inner,
sizeof(iph_inner)) < 0)
Expand All @@ -83,30 +95,58 @@ static __always_inline int encap_ipv4(struct __sk_buff *skb, __u8 encap_proto)
return TC_ACT_OK;

olen = sizeof(h_outer.ip);
l2_len = 0;

flags = BPF_F_ADJ_ROOM_FIXED_GSO | BPF_F_ADJ_ROOM_ENCAP_L3_IPV4;

switch (l2_proto) {
case ETH_P_MPLS_UC:
l2_len = sizeof(mpls_label);
udp_dst = MPLS_OVER_UDP_PORT;
break;
case ETH_P_TEB:
l2_len = ETH_HLEN;
udp_dst = ETH_OVER_UDP_PORT;
break;
}
flags |= BPF_F_ADJ_ROOM_ENCAP_L2(l2_len);

switch (encap_proto) {
case IPPROTO_GRE:
flags |= BPF_F_ADJ_ROOM_ENCAP_L4_GRE;
olen += sizeof(h_outer.l4hdr.gre);
h_outer.l4hdr.gre.protocol = bpf_htons(ETH_P_IP);
h_outer.l4hdr.gre.protocol = bpf_htons(l2_proto);
h_outer.l4hdr.gre.flags = 0;
break;
case IPPROTO_UDP:
flags |= BPF_F_ADJ_ROOM_ENCAP_L4_UDP;
olen += sizeof(h_outer.l4hdr.udp);
h_outer.l4hdr.udp.source = __bpf_constant_htons(cfg_udp_src);
h_outer.l4hdr.udp.dest = __bpf_constant_htons(cfg_udp_dst);
h_outer.l4hdr.udp.dest = bpf_htons(udp_dst);
h_outer.l4hdr.udp.check = 0;
h_outer.l4hdr.udp.len = bpf_htons(bpf_ntohs(iph_inner.tot_len) +
sizeof(h_outer.l4hdr.udp));
sizeof(h_outer.l4hdr.udp) +
l2_len);
break;
case IPPROTO_IPIP:
break;
default:
return TC_ACT_OK;
}

/* add L2 encap (if specified) */
switch (l2_proto) {
case ETH_P_MPLS_UC:
*((__u32 *)((__u8 *)&h_outer + olen)) = mpls_label;
break;
case ETH_P_TEB:
if (bpf_skb_load_bytes(skb, 0, (__u8 *)&h_outer + olen,
ETH_HLEN))
return TC_ACT_SHOT;
break;
}
olen += l2_len;

/* add room between mac and network header */
if (bpf_skb_adjust_room(skb, olen, BPF_ADJ_ROOM_MAC, flags))
return TC_ACT_SHOT;
Expand All @@ -127,14 +167,16 @@ static __always_inline int encap_ipv4(struct __sk_buff *skb, __u8 encap_proto)
return TC_ACT_OK;
}

static __always_inline int encap_ipv6(struct __sk_buff *skb, __u8 encap_proto)
static __always_inline int encap_ipv6(struct __sk_buff *skb, __u8 encap_proto,
__u16 l2_proto)
{
__u16 udp_dst = UDP_PORT;
struct ipv6hdr iph_inner;
struct v6hdr h_outer;
struct tcphdr tcph;
int olen, l2_len;
__u16 tot_len;
__u64 flags;
int olen;

if (bpf_skb_load_bytes(skb, ETH_HLEN, &iph_inner,
sizeof(iph_inner)) < 0)
Expand All @@ -149,20 +191,34 @@ static __always_inline int encap_ipv6(struct __sk_buff *skb, __u8 encap_proto)
return TC_ACT_OK;

olen = sizeof(h_outer.ip);
l2_len = 0;

flags = BPF_F_ADJ_ROOM_FIXED_GSO | BPF_F_ADJ_ROOM_ENCAP_L3_IPV6;

switch (l2_proto) {
case ETH_P_MPLS_UC:
l2_len = sizeof(mpls_label);
udp_dst = MPLS_OVER_UDP_PORT;
break;
case ETH_P_TEB:
l2_len = ETH_HLEN;
udp_dst = ETH_OVER_UDP_PORT;
break;
}
flags |= BPF_F_ADJ_ROOM_ENCAP_L2(l2_len);

switch (encap_proto) {
case IPPROTO_GRE:
flags |= BPF_F_ADJ_ROOM_ENCAP_L4_GRE;
olen += sizeof(h_outer.l4hdr.gre);
h_outer.l4hdr.gre.protocol = bpf_htons(ETH_P_IPV6);
h_outer.l4hdr.gre.protocol = bpf_htons(l2_proto);
h_outer.l4hdr.gre.flags = 0;
break;
case IPPROTO_UDP:
flags |= BPF_F_ADJ_ROOM_ENCAP_L4_UDP;
olen += sizeof(h_outer.l4hdr.udp);
h_outer.l4hdr.udp.source = __bpf_constant_htons(cfg_udp_src);
h_outer.l4hdr.udp.dest = __bpf_constant_htons(cfg_udp_dst);
h_outer.l4hdr.udp.dest = bpf_htons(udp_dst);
tot_len = bpf_ntohs(iph_inner.payload_len) + sizeof(iph_inner) +
sizeof(h_outer.l4hdr.udp);
h_outer.l4hdr.udp.check = 0;
Expand All @@ -174,6 +230,19 @@ static __always_inline int encap_ipv6(struct __sk_buff *skb, __u8 encap_proto)
return TC_ACT_OK;
}

/* add L2 encap (if specified) */
switch (l2_proto) {
case ETH_P_MPLS_UC:
*((__u32 *)((__u8 *)&h_outer + olen)) = mpls_label;
break;
case ETH_P_TEB:
if (bpf_skb_load_bytes(skb, 0, (__u8 *)&h_outer + olen,
ETH_HLEN))
return TC_ACT_SHOT;
break;
}
olen += l2_len;

/* add room between mac and network header */
if (bpf_skb_adjust_room(skb, olen, BPF_ADJ_ROOM_MAC, flags))
return TC_ACT_SHOT;
Expand All @@ -193,63 +262,137 @@ static __always_inline int encap_ipv6(struct __sk_buff *skb, __u8 encap_proto)
return TC_ACT_OK;
}

SEC("encap_ipip")
int __encap_ipip(struct __sk_buff *skb)
SEC("encap_ipip_none")
int __encap_ipip_none(struct __sk_buff *skb)
{
if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
return encap_ipv4(skb, IPPROTO_IPIP, ETH_P_IP);
else
return TC_ACT_OK;
}

SEC("encap_gre_none")
int __encap_gre_none(struct __sk_buff *skb)
{
if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
return encap_ipv4(skb, IPPROTO_GRE, ETH_P_IP);
else
return TC_ACT_OK;
}

SEC("encap_gre_mpls")
int __encap_gre_mpls(struct __sk_buff *skb)
{
if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
return encap_ipv4(skb, IPPROTO_GRE, ETH_P_MPLS_UC);
else
return TC_ACT_OK;
}

SEC("encap_gre_eth")
int __encap_gre_eth(struct __sk_buff *skb)
{
if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
return encap_ipv4(skb, IPPROTO_IPIP);
return encap_ipv4(skb, IPPROTO_GRE, ETH_P_TEB);
else
return TC_ACT_OK;
}

SEC("encap_gre")
int __encap_gre(struct __sk_buff *skb)
SEC("encap_udp_none")
int __encap_udp_none(struct __sk_buff *skb)
{
if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
return encap_ipv4(skb, IPPROTO_GRE);
return encap_ipv4(skb, IPPROTO_UDP, ETH_P_IP);
else
return TC_ACT_OK;
}

SEC("encap_udp")
int __encap_udp(struct __sk_buff *skb)
SEC("encap_udp_mpls")
int __encap_udp_mpls(struct __sk_buff *skb)
{
if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
return encap_ipv4(skb, IPPROTO_UDP);
return encap_ipv4(skb, IPPROTO_UDP, ETH_P_MPLS_UC);
else
return TC_ACT_OK;
}

SEC("encap_udp_eth")
int __encap_udp_eth(struct __sk_buff *skb)
{
if (skb->protocol == __bpf_constant_htons(ETH_P_IP))
return encap_ipv4(skb, IPPROTO_UDP, ETH_P_TEB);
else
return TC_ACT_OK;
}

SEC("encap_ip6tnl_none")
int __encap_ip6tnl_none(struct __sk_buff *skb)
{
if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
return encap_ipv6(skb, IPPROTO_IPV6, ETH_P_IPV6);
else
return TC_ACT_OK;
}

SEC("encap_ip6gre_none")
int __encap_ip6gre_none(struct __sk_buff *skb)
{
if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
return encap_ipv6(skb, IPPROTO_GRE, ETH_P_IPV6);
else
return TC_ACT_OK;
}

SEC("encap_ip6gre_mpls")
int __encap_ip6gre_mpls(struct __sk_buff *skb)
{
if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
return encap_ipv6(skb, IPPROTO_GRE, ETH_P_MPLS_UC);
else
return TC_ACT_OK;
}

SEC("encap_ip6gre_eth")
int __encap_ip6gre_eth(struct __sk_buff *skb)
{
if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
return encap_ipv6(skb, IPPROTO_GRE, ETH_P_TEB);
else
return TC_ACT_OK;
}

SEC("encap_ip6tnl")
int __encap_ip6tnl(struct __sk_buff *skb)
SEC("encap_ip6udp_none")
int __encap_ip6udp_none(struct __sk_buff *skb)
{
if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
return encap_ipv6(skb, IPPROTO_IPV6);
return encap_ipv6(skb, IPPROTO_UDP, ETH_P_IPV6);
else
return TC_ACT_OK;
}

SEC("encap_ip6gre")
int __encap_ip6gre(struct __sk_buff *skb)
SEC("encap_ip6udp_mpls")
int __encap_ip6udp_mpls(struct __sk_buff *skb)
{
if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
return encap_ipv6(skb, IPPROTO_GRE);
return encap_ipv6(skb, IPPROTO_UDP, ETH_P_MPLS_UC);
else
return TC_ACT_OK;
}

SEC("encap_ip6udp")
int __encap_ip6udp(struct __sk_buff *skb)
SEC("encap_ip6udp_eth")
int __encap_ip6udp_eth(struct __sk_buff *skb)
{
if (skb->protocol == __bpf_constant_htons(ETH_P_IPV6))
return encap_ipv6(skb, IPPROTO_UDP);
return encap_ipv6(skb, IPPROTO_UDP, ETH_P_TEB);
else
return TC_ACT_OK;
}

static int decap_internal(struct __sk_buff *skb, int off, int len, char proto)
{
char buf[sizeof(struct v6hdr)];
struct gre_hdr greh;
struct udphdr udph;
int olen = len;

switch (proto) {
Expand All @@ -258,9 +401,29 @@ static int decap_internal(struct __sk_buff *skb, int off, int len, char proto)
break;
case IPPROTO_GRE:
olen += sizeof(struct gre_hdr);
if (bpf_skb_load_bytes(skb, off + len, &greh, sizeof(greh)) < 0)
return TC_ACT_OK;
switch (bpf_ntohs(greh.protocol)) {
case ETH_P_MPLS_UC:
olen += sizeof(mpls_label);
break;
case ETH_P_TEB:
olen += ETH_HLEN;
break;
}
break;
case IPPROTO_UDP:
olen += sizeof(struct udphdr);
if (bpf_skb_load_bytes(skb, off + len, &udph, sizeof(udph)) < 0)
return TC_ACT_OK;
switch (bpf_ntohs(udph.dest)) {
case MPLS_OVER_UDP_PORT:
olen += sizeof(mpls_label);
break;
case ETH_OVER_UDP_PORT:
olen += ETH_HLEN;
break;
}
break;
default:
return TC_ACT_OK;
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