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Diffstat (limited to '')
| -rw-r--r-- | tools/testing/selftests/bpf/sendmsg4_prog.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/sendmsg4_prog.c b/tools/testing/selftests/bpf/sendmsg4_prog.c new file mode 100644 index 000000000..a91536b1c --- /dev/null +++ b/tools/testing/selftests/bpf/sendmsg4_prog.c @@ -0,0 +1,49 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2018 Facebook + +#include <linux/stddef.h> +#include <linux/bpf.h> +#include <sys/socket.h> + +#include "bpf_helpers.h" +#include "bpf_endian.h" + +#define SRC1_IP4 0xAC100001U /* 172.16.0.1 */ +#define SRC2_IP4 0x00000000U +#define SRC_REWRITE_IP4 0x7f000004U +#define DST_IP4 0xC0A801FEU /* 192.168.1.254 */ +#define DST_REWRITE_IP4 0x7f000001U +#define DST_PORT 4040 +#define DST_REWRITE_PORT4 4444 + +int _version SEC("version") = 1; + +SEC("cgroup/sendmsg4") +int sendmsg_v4_prog(struct bpf_sock_addr *ctx) +{ + if (ctx->type != SOCK_DGRAM) + return 0; + + /* Rewrite source. */ + if (ctx->msg_src_ip4 == bpf_htonl(SRC1_IP4) || + ctx->msg_src_ip4 == bpf_htonl(SRC2_IP4)) { + ctx->msg_src_ip4 = bpf_htonl(SRC_REWRITE_IP4); + } else { + /* Unexpected source. Reject sendmsg. */ + return 0; + } + + /* Rewrite destination. */ + if ((ctx->user_ip4 >> 24) == (bpf_htonl(DST_IP4) >> 24) && + ctx->user_port == bpf_htons(DST_PORT)) { + ctx->user_ip4 = bpf_htonl(DST_REWRITE_IP4); + ctx->user_port = bpf_htons(DST_REWRITE_PORT4); + } else { + /* Unexpected source. Reject sendmsg. */ + return 0; + } + + return 1; +} + +char _license[] SEC("license") = "GPL"; |