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LorenzoBianconianakryiko
LorenzoBianconi
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samples: bpf: Convert xdp_router_ipv4 to XDP samples helper
Rely on the libbpf skeleton facility and other utilities provided by XDP sample helpers in xdp_router_ipv4 sample. Signed-off-by: Lorenzo Bianconi <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/7f4d98ee2c13c04d5eb924eebf79ced32fee8418.1647414711.git.lorenzo@kernel.org
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-459
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4 files changed

+381
-459
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‎samples/bpf/Makefile

Lines changed: 6 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -96,7 +96,6 @@ test_cgrp2_sock2-objs := test_cgrp2_sock2.o
9696
xdp1-objs := xdp1_user.o
9797
# reuse xdp1 source intentionally
9898
xdp2-objs := xdp1_user.o
99-
xdp_router_ipv4-objs := xdp_router_ipv4_user.o
10099
test_current_task_under_cgroup-objs := $(CGROUP_HELPERS) \
101100
test_current_task_under_cgroup_user.o
102101
trace_event-objs := trace_event_user.o $(TRACE_HELPERS)
@@ -124,6 +123,7 @@ xdp_redirect_cpu-objs := xdp_redirect_cpu_user.o $(XDP_SAMPLE)
124123
xdp_redirect_map-objs := xdp_redirect_map_user.o $(XDP_SAMPLE)
125124
xdp_redirect-objs := xdp_redirect_user.o $(XDP_SAMPLE)
126125
xdp_monitor-objs := xdp_monitor_user.o $(XDP_SAMPLE)
126+
xdp_router_ipv4-objs := xdp_router_ipv4_user.o $(XDP_SAMPLE)
127127

128128
# Tell kbuild to always build the programs
129129
always-y := $(tprogs-y)
@@ -153,7 +153,6 @@ always-y += parse_varlen.o parse_simple.o parse_ldabs.o
153153
always-y += test_cgrp2_tc_kern.o
154154
always-y += xdp1_kern.o
155155
always-y += xdp2_kern.o
156-
always-y += xdp_router_ipv4_kern.o
157156
always-y += test_current_task_under_cgroup_kern.o
158157
always-y += trace_event_kern.o
159158
always-y += sampleip_kern.o
@@ -342,6 +341,7 @@ $(obj)/xdp_redirect_map_multi_user.o: $(obj)/xdp_redirect_map_multi.skel.h
342341
$(obj)/xdp_redirect_map_user.o: $(obj)/xdp_redirect_map.skel.h
343342
$(obj)/xdp_redirect_user.o: $(obj)/xdp_redirect.skel.h
344343
$(obj)/xdp_monitor_user.o: $(obj)/xdp_monitor.skel.h
344+
$(obj)/xdp_router_ipv4_user.o: $(obj)/xdp_router_ipv4.skel.h
345345

346346
$(obj)/tracex5_kern.o: $(obj)/syscall_nrs.h
347347
$(obj)/hbm_out_kern.o: $(src)/hbm.h $(src)/hbm_kern.h
@@ -399,6 +399,7 @@ $(obj)/xdp_redirect_map_multi.bpf.o: $(obj)/xdp_sample.bpf.o
399399
$(obj)/xdp_redirect_map.bpf.o: $(obj)/xdp_sample.bpf.o
400400
$(obj)/xdp_redirect.bpf.o: $(obj)/xdp_sample.bpf.o
401401
$(obj)/xdp_monitor.bpf.o: $(obj)/xdp_sample.bpf.o
402+
$(obj)/xdp_router_ipv4.bpf.o: $(obj)/xdp_sample.bpf.o
402403

403404
$(obj)/%.bpf.o: $(src)/%.bpf.c $(obj)/vmlinux.h $(src)/xdp_sample.bpf.h $(src)/xdp_sample_shared.h
404405
@echo " CLANG-BPF " $@
@@ -409,14 +410,16 @@ $(obj)/%.bpf.o: $(src)/%.bpf.c $(obj)/vmlinux.h $(src)/xdp_sample.bpf.h $(src)/x
409410
-c $(filter %.bpf.c,$^) -o $@
410411

411412
LINKED_SKELS := xdp_redirect_cpu.skel.h xdp_redirect_map_multi.skel.h \
412-
xdp_redirect_map.skel.h xdp_redirect.skel.h xdp_monitor.skel.h
413+
xdp_redirect_map.skel.h xdp_redirect.skel.h xdp_monitor.skel.h \
414+
xdp_router_ipv4.skel.h
413415
clean-files += $(LINKED_SKELS)
414416

415417
xdp_redirect_cpu.skel.h-deps := xdp_redirect_cpu.bpf.o xdp_sample.bpf.o
416418
xdp_redirect_map_multi.skel.h-deps := xdp_redirect_map_multi.bpf.o xdp_sample.bpf.o
417419
xdp_redirect_map.skel.h-deps := xdp_redirect_map.bpf.o xdp_sample.bpf.o
418420
xdp_redirect.skel.h-deps := xdp_redirect.bpf.o xdp_sample.bpf.o
419421
xdp_monitor.skel.h-deps := xdp_monitor.bpf.o xdp_sample.bpf.o
422+
xdp_router_ipv4.skel.h-deps := xdp_router_ipv4.bpf.o xdp_sample.bpf.o
420423

421424
LINKED_BPF_SRCS := $(patsubst %.bpf.o,%.bpf.c,$(foreach skel,$(LINKED_SKELS),$($(skel)-deps)))
422425

‎samples/bpf/xdp_router_ipv4.bpf.c

Lines changed: 180 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,180 @@
1+
/* Copyright (C) 2017 Cavium, Inc.
2+
*
3+
* This program is free software; you can redistribute it and/or modify it
4+
* under the terms of version 2 of the GNU General Public License
5+
* as published by the Free Software Foundation.
6+
*/
7+
8+
#include "vmlinux.h"
9+
#include "xdp_sample.bpf.h"
10+
#include "xdp_sample_shared.h"
11+
12+
#define ETH_ALEN 6
13+
#define ETH_P_8021Q 0x8100
14+
#define ETH_P_8021AD 0x88A8
15+
16+
struct trie_value {
17+
__u8 prefix[4];
18+
__be64 value;
19+
int ifindex;
20+
int metric;
21+
__be32 gw;
22+
};
23+
24+
/* Key for lpm_trie */
25+
union key_4 {
26+
u32 b32[2];
27+
u8 b8[8];
28+
};
29+
30+
struct arp_entry {
31+
__be64 mac;
32+
__be32 dst;
33+
};
34+
35+
struct direct_map {
36+
struct arp_entry arp;
37+
int ifindex;
38+
__be64 mac;
39+
};
40+
41+
/* Map for trie implementation */
42+
struct {
43+
__uint(type, BPF_MAP_TYPE_LPM_TRIE);
44+
__uint(key_size, 8);
45+
__uint(value_size, sizeof(struct trie_value));
46+
__uint(max_entries, 50);
47+
__uint(map_flags, BPF_F_NO_PREALLOC);
48+
} lpm_map SEC(".maps");
49+
50+
/* Map for ARP table */
51+
struct {
52+
__uint(type, BPF_MAP_TYPE_HASH);
53+
__type(key, __be32);
54+
__type(value, __be64);
55+
__uint(max_entries, 50);
56+
} arp_table SEC(".maps");
57+
58+
/* Map to keep the exact match entries in the route table */
59+
struct {
60+
__uint(type, BPF_MAP_TYPE_HASH);
61+
__type(key, __be32);
62+
__type(value, struct direct_map);
63+
__uint(max_entries, 50);
64+
} exact_match SEC(".maps");
65+
66+
struct {
67+
__uint(type, BPF_MAP_TYPE_DEVMAP);
68+
__uint(key_size, sizeof(int));
69+
__uint(value_size, sizeof(int));
70+
__uint(max_entries, 100);
71+
} tx_port SEC(".maps");
72+
73+
SEC("xdp")
74+
int xdp_router_ipv4_prog(struct xdp_md *ctx)
75+
{
76+
void *data_end = (void *)(long)ctx->data_end;
77+
void *data = (void *)(long)ctx->data;
78+
struct ethhdr *eth = data;
79+
u64 nh_off = sizeof(*eth);
80+
struct datarec *rec;
81+
__be16 h_proto;
82+
u32 key = 0;
83+
84+
rec = bpf_map_lookup_elem(&rx_cnt, &key);
85+
if (rec)
86+
NO_TEAR_INC(rec->processed);
87+
88+
if (data + nh_off > data_end)
89+
goto drop;
90+
91+
h_proto = eth->h_proto;
92+
if (h_proto == bpf_htons(ETH_P_8021Q) ||
93+
h_proto == bpf_htons(ETH_P_8021AD)) {
94+
struct vlan_hdr *vhdr;
95+
96+
vhdr = data + nh_off;
97+
nh_off += sizeof(struct vlan_hdr);
98+
if (data + nh_off > data_end)
99+
goto drop;
100+
101+
h_proto = vhdr->h_vlan_encapsulated_proto;
102+
}
103+
104+
switch (bpf_ntohs(h_proto)) {
105+
case ETH_P_ARP:
106+
if (rec)
107+
NO_TEAR_INC(rec->xdp_pass);
108+
return XDP_PASS;
109+
case ETH_P_IP: {
110+
struct iphdr *iph = data + nh_off;
111+
struct direct_map *direct_entry;
112+
__be64 *dest_mac, *src_mac;
113+
int forward_to;
114+
115+
if (iph + 1 > data_end)
116+
goto drop;
117+
118+
direct_entry = bpf_map_lookup_elem(&exact_match, &iph->daddr);
119+
120+
/* Check for exact match, this would give a faster lookup */
121+
if (direct_entry && direct_entry->mac &&
122+
direct_entry->arp.mac) {
123+
src_mac = &direct_entry->mac;
124+
dest_mac = &direct_entry->arp.mac;
125+
forward_to = direct_entry->ifindex;
126+
} else {
127+
struct trie_value *prefix_value;
128+
union key_4 key4;
129+
130+
/* Look up in the trie for lpm */
131+
key4.b32[0] = 32;
132+
key4.b8[4] = iph->daddr & 0xff;
133+
key4.b8[5] = (iph->daddr >> 8) & 0xff;
134+
key4.b8[6] = (iph->daddr >> 16) & 0xff;
135+
key4.b8[7] = (iph->daddr >> 24) & 0xff;
136+
137+
prefix_value = bpf_map_lookup_elem(&lpm_map, &key4);
138+
if (!prefix_value)
139+
goto drop;
140+
141+
forward_to = prefix_value->ifindex;
142+
src_mac = &prefix_value->value;
143+
if (!src_mac)
144+
goto drop;
145+
146+
dest_mac = bpf_map_lookup_elem(&arp_table, &iph->daddr);
147+
if (!dest_mac) {
148+
if (!prefix_value->gw)
149+
goto drop;
150+
151+
dest_mac = bpf_map_lookup_elem(&arp_table,
152+
&prefix_value->gw);
153+
}
154+
}
155+
156+
if (src_mac && dest_mac) {
157+
int ret;
158+
159+
__builtin_memcpy(eth->h_dest, dest_mac, ETH_ALEN);
160+
__builtin_memcpy(eth->h_source, src_mac, ETH_ALEN);
161+
162+
ret = bpf_redirect_map(&tx_port, forward_to, 0);
163+
if (ret == XDP_REDIRECT) {
164+
if (rec)
165+
NO_TEAR_INC(rec->xdp_redirect);
166+
return ret;
167+
}
168+
}
169+
}
170+
default:
171+
break;
172+
}
173+
drop:
174+
if (rec)
175+
NO_TEAR_INC(rec->xdp_drop);
176+
177+
return XDP_DROP;
178+
}
179+
180+
char _license[] SEC("license") = "GPL";

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