diff options
Diffstat (limited to 'tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c b/tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c new file mode 100644 index 000000000..49a84a3a2 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c @@ -0,0 +1,181 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2019 Facebook */ +#include <linux/stddef.h> +#include <linux/if_ether.h> +#include <linux/ipv6.h> +#include <linux/bpf.h> +#include <linux/tcp.h> +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_endian.h> +#include <bpf/bpf_tracing.h> + +struct sk_buff { + unsigned int len; +}; + +__u64 test_result = 0; +SEC("fexit/test_pkt_access") +int BPF_PROG(test_main, struct sk_buff *skb, int ret) +{ + int len; + + __builtin_preserve_access_index(({ + len = skb->len; + })); + if (len != 74 || ret != 0) + return 0; + test_result = 1; + return 0; +} + +__u64 test_result_subprog1 = 0; +SEC("fexit/test_pkt_access_subprog1") +int BPF_PROG(test_subprog1, struct sk_buff *skb, int ret) +{ + int len; + + __builtin_preserve_access_index(({ + len = skb->len; + })); + if (len != 74 || ret != 148) + return 0; + test_result_subprog1 = 1; + return 0; +} + +/* Though test_pkt_access_subprog2() is defined in C as: + * static __attribute__ ((noinline)) + * int test_pkt_access_subprog2(int val, volatile struct __sk_buff *skb) + * { + * return skb->len * val; + * } + * llvm optimizations remove 'int val' argument and generate BPF assembly: + * r0 = *(u32 *)(r1 + 0) + * w0 <<= 1 + * exit + * In such case the verifier falls back to conservative and + * tracing program can access arguments and return value as u64 + * instead of accurate types. + */ +struct args_subprog2 { + __u64 args[5]; + __u64 ret; +}; +__u64 test_result_subprog2 = 0; +SEC("fexit/test_pkt_access_subprog2") +int test_subprog2(struct args_subprog2 *ctx) +{ + struct sk_buff *skb = (void *)ctx->args[0]; + __u64 ret; + int len; + + bpf_probe_read_kernel(&len, sizeof(len), + __builtin_preserve_access_index(&skb->len)); + + ret = ctx->ret; + /* bpf_prog_load() loads "test_pkt_access.o" with BPF_F_TEST_RND_HI32 + * which randomizes upper 32 bits after BPF_ALU32 insns. + * Hence after 'w0 <<= 1' upper bits of $rax are random. + * That is expected and correct. Trim them. + */ + ret = (__u32) ret; + if (len != 74 || ret != 148) + return 0; + test_result_subprog2 = 1; + return 0; +} + +__u64 test_result_subprog3 = 0; +SEC("fexit/test_pkt_access_subprog3") +int BPF_PROG(test_subprog3, int val, struct sk_buff *skb, int ret) +{ + int len; + + __builtin_preserve_access_index(({ + len = skb->len; + })); + if (len != 74 || ret != 74 * val || val != 3) + return 0; + test_result_subprog3 = 1; + return 0; +} + +__u64 test_get_skb_len = 0; +SEC("freplace/get_skb_len") +int new_get_skb_len(struct __sk_buff *skb) +{ + int len = skb->len; + + if (len != 74) + return 0; + test_get_skb_len = 1; + return 74; /* original get_skb_len() returns skb->len */ +} + +__u64 test_get_skb_ifindex = 0; +SEC("freplace/get_skb_ifindex") +int new_get_skb_ifindex(int val, struct __sk_buff *skb, int var) +{ + void *data_end = (void *)(long)skb->data_end; + void *data = (void *)(long)skb->data; + struct ipv6hdr ip6, *ip6p; + int ifindex = skb->ifindex; + __u32 eth_proto; + __u32 nh_off; + + /* check that BPF extension can read packet via direct packet access */ + if (data + 14 + sizeof(ip6) > data_end) + return 0; + ip6p = data + 14; + + if (ip6p->nexthdr != 6 || ip6p->payload_len != __bpf_constant_htons(123)) + return 0; + + /* check that legacy packet access helper works too */ + if (bpf_skb_load_bytes(skb, 14, &ip6, sizeof(ip6)) < 0) + return 0; + ip6p = &ip6; + if (ip6p->nexthdr != 6 || ip6p->payload_len != __bpf_constant_htons(123)) + return 0; + + if (ifindex != 1 || val != 3 || var != 1) + return 0; + test_get_skb_ifindex = 1; + return 3; /* original get_skb_ifindex() returns val * ifindex * var */ +} + +volatile __u64 test_get_constant = 0; +SEC("freplace/get_constant") +int new_get_constant(long val) +{ + if (val != 123) + return 0; + test_get_constant = 1; + return test_get_constant; /* original get_constant() returns val - 122 */ +} + +__u64 test_pkt_write_access_subprog = 0; +SEC("freplace/test_pkt_write_access_subprog") +int new_test_pkt_write_access_subprog(struct __sk_buff *skb, __u32 off) +{ + + void *data = (void *)(long)skb->data; + void *data_end = (void *)(long)skb->data_end; + struct tcphdr *tcp; + + if (off > sizeof(struct ethhdr) + sizeof(struct ipv6hdr)) + return -1; + + tcp = data + off; + if (tcp + 1 > data_end) + return -1; + + /* make modifications to the packet data */ + tcp->check++; + tcp->syn = 0; + + test_pkt_write_access_subprog = 1; + return 0; +} + +char _license[] SEC("license") = "GPL"; |