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Commit 04b6ab73 authored by Andrey Ignatov's avatar Andrey Ignatov Committed by Daniel Borkmann
Browse files

selftests/bpf: Selftest for sys_sendmsg hooks 



Add selftest for BPF_CGROUP_UDP4_SENDMSG and BPF_CGROUP_UDP6_SENDMSG
attach types.

Try to sendmsg(2) to specific IP:port and test that:
* source IP is overridden as expected.
* remote IP:port pair is overridden as expected;

Both UDPv4 and UDPv6 are tested.

Output:
  # test_sock_addr.sh 2>/dev/null
  Wait for testing IPv4/IPv6 to become available ... OK
  ... pre-existing test-cases skipped ...
  Test case: sendmsg4: load prog with wrong expected attach type .. [PASS]
  Test case: sendmsg4: attach prog with wrong attach type .. [PASS]
  Test case: sendmsg4: rewrite IP & port (asm) .. [PASS]
  Test case: sendmsg4: rewrite IP & port (C) .. [PASS]
  Test case: sendmsg4: deny call .. [PASS]
  Test case: sendmsg6: load prog with wrong expected attach type .. [PASS]
  Test case: sendmsg6: attach prog with wrong attach type .. [PASS]
  Test case: sendmsg6: rewrite IP & port (asm) .. [PASS]
  Test case: sendmsg6: rewrite IP & port (C) .. [PASS]
  Test case: sendmsg6: IPv4-mapped IPv6 .. [PASS]
  Test case: sendmsg6: deny call .. [PASS]
  Summary: 27 PASSED, 0 FAILED

Signed-off-by: default avatarAndrey Ignatov <rdna@fb.com>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 9be71aa6

tools/testing/selftests/bpf/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -34,7 +34,7 @@ TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test 
	sockmap_tcp_msg_prog.o connect4_prog.o connect6_prog.o test_adjust_tail.o \

	test_btf_haskv.o test_btf_nokv.o test_sockmap_kern.o test_tunnel_kern.o \

	test_get_stack_rawtp.o test_sockmap_kern.o test_sockhash_kern.o \

	test_lwt_seg6local.o

	test_lwt_seg6local.o sendmsg4_prog.o sendmsg6_prog.o



# Order correspond to 'make run_tests' order

TEST_PROGS := test_kmod.sh \

tools/testing/selftests/bpf/sendmsg4_prog.c

0 → 100644
+49 −0
Original line number Diff line number Diff line 
// 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";

tools/testing/selftests/bpf/sendmsg6_prog.c

0 → 100644
+60 −0
Original line number Diff line number Diff line 
// 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 SRC_REWRITE_IP6_0	0

#define SRC_REWRITE_IP6_1	0

#define SRC_REWRITE_IP6_2	0

#define SRC_REWRITE_IP6_3	6



#define DST_REWRITE_IP6_0	0

#define DST_REWRITE_IP6_1	0

#define DST_REWRITE_IP6_2	0

#define DST_REWRITE_IP6_3	1



#define DST_REWRITE_PORT6	6666



int _version SEC("version") = 1;



SEC("cgroup/sendmsg6")

int sendmsg_v6_prog(struct bpf_sock_addr *ctx)

{

	if (ctx->type != SOCK_DGRAM)

		return 0;



	/* Rewrite source. */

	if (ctx->msg_src_ip6[3] == bpf_htonl(1) ||

	    ctx->msg_src_ip6[3] == bpf_htonl(0)) {

		ctx->msg_src_ip6[0] = bpf_htonl(SRC_REWRITE_IP6_0);

		ctx->msg_src_ip6[1] = bpf_htonl(SRC_REWRITE_IP6_1);

		ctx->msg_src_ip6[2] = bpf_htonl(SRC_REWRITE_IP6_2);

		ctx->msg_src_ip6[3] = bpf_htonl(SRC_REWRITE_IP6_3);

	} else {

		/* Unexpected source. Reject sendmsg. */

		return 0;

	}



	/* Rewrite destination. */

	if ((ctx->user_ip6[0] & 0xFFFF) == bpf_htons(0xFACE) &&

	     ctx->user_ip6[0] >> 16 == bpf_htons(0xB00C)) {

		ctx->user_ip6[0] = bpf_htonl(DST_REWRITE_IP6_0);

		ctx->user_ip6[1] = bpf_htonl(DST_REWRITE_IP6_1);

		ctx->user_ip6[2] = bpf_htonl(DST_REWRITE_IP6_2);

		ctx->user_ip6[3] = bpf_htonl(DST_REWRITE_IP6_3);



		ctx->user_port = bpf_htons(DST_REWRITE_PORT6);

	} else {

		/* Unexpected destination. Reject sendmsg. */

		return 0;

	}



	return 1;

}



char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/test_sock_addr.c

+518 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

// Copyright (c) 2018 Facebook



#define _GNU_SOURCE



#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>



#include <arpa/inet.h>

#include <netinet/in.h>

#include <sys/types.h>

#include <sys/select.h>

#include <sys/socket.h>



#include <linux/filter.h>
@@ -17,6 +21,10 @@ 
#include "cgroup_helpers.h"

#include "bpf_rlimit.h"



#ifndef ENOTSUPP

# define ENOTSUPP 524

#endif



#ifndef ARRAY_SIZE

# define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))

#endif
@@ -24,15 +32,20 @@ 
#define CG_PATH	"/foo"

#define CONNECT4_PROG_PATH	"./connect4_prog.o"

#define CONNECT6_PROG_PATH	"./connect6_prog.o"

#define SENDMSG4_PROG_PATH	"./sendmsg4_prog.o"

#define SENDMSG6_PROG_PATH	"./sendmsg6_prog.o"



#define SERV4_IP		"192.168.1.254"

#define SERV4_REWRITE_IP	"127.0.0.1"

#define SRC4_IP			"172.16.0.1"

#define SRC4_REWRITE_IP		"127.0.0.4"

#define SERV4_PORT		4040

#define SERV4_REWRITE_PORT	4444



#define SERV6_IP		"face:b00c:1234:5678::abcd"

#define SERV6_REWRITE_IP	"::1"

#define SERV6_V4MAPPED_IP	"::ffff:192.168.0.4"

#define SRC6_IP			"::1"

#define SRC6_REWRITE_IP		"::6"

#define SERV6_PORT		6060

#define SERV6_REWRITE_PORT	6666
@@ -65,6 +78,8 @@ struct sock_addr_test { 
	enum {

		LOAD_REJECT,

		ATTACH_REJECT,

		SYSCALL_EPERM,

		SYSCALL_ENOTSUPP,

		SUCCESS,

	} expected_result;

};
@@ -73,6 +88,12 @@ static int bind4_prog_load(const struct sock_addr_test *test); 
static int bind6_prog_load(const struct sock_addr_test *test);

static int connect4_prog_load(const struct sock_addr_test *test);

static int connect6_prog_load(const struct sock_addr_test *test);

static int sendmsg_deny_prog_load(const struct sock_addr_test *test);

static int sendmsg4_rw_asm_prog_load(const struct sock_addr_test *test);

static int sendmsg4_rw_c_prog_load(const struct sock_addr_test *test);

static int sendmsg6_rw_asm_prog_load(const struct sock_addr_test *test);

static int sendmsg6_rw_c_prog_load(const struct sock_addr_test *test);

static int sendmsg6_rw_v4mapped_prog_load(const struct sock_addr_test *test);



static struct sock_addr_test tests[] = {

	/* bind */
@@ -302,6 +323,162 @@ static struct sock_addr_test tests[] = { 
		SRC6_REWRITE_IP,

		SUCCESS,

	},



	/* sendmsg */

	{

		"sendmsg4: load prog with wrong expected attach type",

		sendmsg4_rw_asm_prog_load,

		BPF_CGROUP_UDP6_SENDMSG,

		BPF_CGROUP_UDP4_SENDMSG,

		AF_INET,

		SOCK_DGRAM,

		NULL,

		0,

		NULL,

		0,

		NULL,

		LOAD_REJECT,

	},

	{

		"sendmsg4: attach prog with wrong attach type",

		sendmsg4_rw_asm_prog_load,

		BPF_CGROUP_UDP4_SENDMSG,

		BPF_CGROUP_UDP6_SENDMSG,

		AF_INET,

		SOCK_DGRAM,

		NULL,

		0,

		NULL,

		0,

		NULL,

		ATTACH_REJECT,

	},

	{

		"sendmsg4: rewrite IP & port (asm)",

		sendmsg4_rw_asm_prog_load,

		BPF_CGROUP_UDP4_SENDMSG,

		BPF_CGROUP_UDP4_SENDMSG,

		AF_INET,

		SOCK_DGRAM,

		SERV4_IP,

		SERV4_PORT,

		SERV4_REWRITE_IP,

		SERV4_REWRITE_PORT,

		SRC4_REWRITE_IP,

		SUCCESS,

	},

	{

		"sendmsg4: rewrite IP & port (C)",

		sendmsg4_rw_c_prog_load,

		BPF_CGROUP_UDP4_SENDMSG,

		BPF_CGROUP_UDP4_SENDMSG,

		AF_INET,

		SOCK_DGRAM,

		SERV4_IP,

		SERV4_PORT,

		SERV4_REWRITE_IP,

		SERV4_REWRITE_PORT,

		SRC4_REWRITE_IP,

		SUCCESS,

	},

	{

		"sendmsg4: deny call",

		sendmsg_deny_prog_load,

		BPF_CGROUP_UDP4_SENDMSG,

		BPF_CGROUP_UDP4_SENDMSG,

		AF_INET,

		SOCK_DGRAM,

		SERV4_IP,

		SERV4_PORT,

		SERV4_REWRITE_IP,

		SERV4_REWRITE_PORT,

		SRC4_REWRITE_IP,

		SYSCALL_EPERM,

	},

	{

		"sendmsg6: load prog with wrong expected attach type",

		sendmsg6_rw_asm_prog_load,

		BPF_CGROUP_UDP4_SENDMSG,

		BPF_CGROUP_UDP6_SENDMSG,

		AF_INET6,

		SOCK_DGRAM,

		NULL,

		0,

		NULL,

		0,

		NULL,

		LOAD_REJECT,

	},

	{

		"sendmsg6: attach prog with wrong attach type",

		sendmsg6_rw_asm_prog_load,

		BPF_CGROUP_UDP6_SENDMSG,

		BPF_CGROUP_UDP4_SENDMSG,

		AF_INET6,

		SOCK_DGRAM,

		NULL,

		0,

		NULL,

		0,

		NULL,

		ATTACH_REJECT,

	},

	{

		"sendmsg6: rewrite IP & port (asm)",

		sendmsg6_rw_asm_prog_load,

		BPF_CGROUP_UDP6_SENDMSG,

		BPF_CGROUP_UDP6_SENDMSG,

		AF_INET6,

		SOCK_DGRAM,

		SERV6_IP,

		SERV6_PORT,

		SERV6_REWRITE_IP,

		SERV6_REWRITE_PORT,

		SRC6_REWRITE_IP,

		SUCCESS,

	},

	{

		"sendmsg6: rewrite IP & port (C)",

		sendmsg6_rw_c_prog_load,

		BPF_CGROUP_UDP6_SENDMSG,

		BPF_CGROUP_UDP6_SENDMSG,

		AF_INET6,

		SOCK_DGRAM,

		SERV6_IP,

		SERV6_PORT,

		SERV6_REWRITE_IP,

		SERV6_REWRITE_PORT,

		SRC6_REWRITE_IP,

		SUCCESS,

	},

	{

		"sendmsg6: IPv4-mapped IPv6",

		sendmsg6_rw_v4mapped_prog_load,

		BPF_CGROUP_UDP6_SENDMSG,

		BPF_CGROUP_UDP6_SENDMSG,

		AF_INET6,

		SOCK_DGRAM,

		SERV6_IP,

		SERV6_PORT,

		SERV6_REWRITE_IP,

		SERV6_REWRITE_PORT,

		SRC6_REWRITE_IP,

		SYSCALL_ENOTSUPP,

	},

	{

		"sendmsg6: deny call",

		sendmsg_deny_prog_load,

		BPF_CGROUP_UDP6_SENDMSG,

		BPF_CGROUP_UDP6_SENDMSG,

		AF_INET6,

		SOCK_DGRAM,

		SERV6_IP,

		SERV6_PORT,

		SERV6_REWRITE_IP,

		SERV6_REWRITE_PORT,

		SRC6_REWRITE_IP,

		SYSCALL_EPERM,

	},

};



static int mk_sockaddr(int domain, const char *ip, unsigned short port,
@@ -540,6 +717,141 @@ static int connect6_prog_load(const struct sock_addr_test *test) 
	return load_path(test, CONNECT6_PROG_PATH);

}



static int sendmsg_deny_prog_load(const struct sock_addr_test *test)

{

	struct bpf_insn insns[] = {

		/* return 0 */

		BPF_MOV64_IMM(BPF_REG_0, 0),

		BPF_EXIT_INSN(),

	};

	return load_insns(test, insns, sizeof(insns) / sizeof(struct bpf_insn));

}



static int sendmsg4_rw_asm_prog_load(const struct sock_addr_test *test)

{

	struct sockaddr_in dst4_rw_addr;

	struct in_addr src4_rw_ip;



	if (inet_pton(AF_INET, SRC4_REWRITE_IP, (void *)&src4_rw_ip) != 1) {

		log_err("Invalid IPv4: %s", SRC4_REWRITE_IP);

		return -1;

	}



	if (mk_sockaddr(AF_INET, SERV4_REWRITE_IP, SERV4_REWRITE_PORT,

			(struct sockaddr *)&dst4_rw_addr,

			sizeof(dst4_rw_addr)) == -1)

		return -1;



	struct bpf_insn insns[] = {

		BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),



		/* if (sk.family == AF_INET && */

		BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,

			    offsetof(struct bpf_sock_addr, family)),

		BPF_JMP_IMM(BPF_JNE, BPF_REG_7, AF_INET, 8),



		/*     sk.type == SOCK_DGRAM)  { */

		BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,

			    offsetof(struct bpf_sock_addr, type)),

		BPF_JMP_IMM(BPF_JNE, BPF_REG_7, SOCK_DGRAM, 6),



		/*      msg_src_ip4 = src4_rw_ip */

		BPF_MOV32_IMM(BPF_REG_7, src4_rw_ip.s_addr),

		BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_7,

			    offsetof(struct bpf_sock_addr, msg_src_ip4)),



		/*      user_ip4 = dst4_rw_addr.sin_addr */

		BPF_MOV32_IMM(BPF_REG_7, dst4_rw_addr.sin_addr.s_addr),

		BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_7,

			    offsetof(struct bpf_sock_addr, user_ip4)),



		/*      user_port = dst4_rw_addr.sin_port */

		BPF_MOV32_IMM(BPF_REG_7, dst4_rw_addr.sin_port),

		BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_7,

			    offsetof(struct bpf_sock_addr, user_port)),

		/* } */



		/* return 1 */

		BPF_MOV64_IMM(BPF_REG_0, 1),

		BPF_EXIT_INSN(),

	};



	return load_insns(test, insns, sizeof(insns) / sizeof(struct bpf_insn));

}



static int sendmsg4_rw_c_prog_load(const struct sock_addr_test *test)

{

	return load_path(test, SENDMSG4_PROG_PATH);

}



static int sendmsg6_rw_dst_asm_prog_load(const struct sock_addr_test *test,

					 const char *rw_dst_ip)

{

	struct sockaddr_in6 dst6_rw_addr;

	struct in6_addr src6_rw_ip;



	if (inet_pton(AF_INET6, SRC6_REWRITE_IP, (void *)&src6_rw_ip) != 1) {

		log_err("Invalid IPv6: %s", SRC6_REWRITE_IP);

		return -1;

	}



	if (mk_sockaddr(AF_INET6, rw_dst_ip, SERV6_REWRITE_PORT,

			(struct sockaddr *)&dst6_rw_addr,

			sizeof(dst6_rw_addr)) == -1)

		return -1;



	struct bpf_insn insns[] = {

		BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),



		/* if (sk.family == AF_INET6) { */

		BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,

			    offsetof(struct bpf_sock_addr, family)),

		BPF_JMP_IMM(BPF_JNE, BPF_REG_7, AF_INET6, 18),



#define STORE_IPV6_WORD_N(DST, SRC, N)					       \

		BPF_MOV32_IMM(BPF_REG_7, SRC[N]),			       \

		BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_7,		       \

			    offsetof(struct bpf_sock_addr, DST[N]))



#define STORE_IPV6(DST, SRC)						       \

		STORE_IPV6_WORD_N(DST, SRC, 0),				       \

		STORE_IPV6_WORD_N(DST, SRC, 1),				       \

		STORE_IPV6_WORD_N(DST, SRC, 2),				       \

		STORE_IPV6_WORD_N(DST, SRC, 3)



		STORE_IPV6(msg_src_ip6, src6_rw_ip.s6_addr32),

		STORE_IPV6(user_ip6, dst6_rw_addr.sin6_addr.s6_addr32),



		/*      user_port = dst6_rw_addr.sin6_port */

		BPF_MOV32_IMM(BPF_REG_7, dst6_rw_addr.sin6_port),

		BPF_STX_MEM(BPF_W, BPF_REG_6, BPF_REG_7,

			    offsetof(struct bpf_sock_addr, user_port)),



		/* } */



		/* return 1 */

		BPF_MOV64_IMM(BPF_REG_0, 1),

		BPF_EXIT_INSN(),

	};



	return load_insns(test, insns, sizeof(insns) / sizeof(struct bpf_insn));

}



static int sendmsg6_rw_asm_prog_load(const struct sock_addr_test *test)

{

	return sendmsg6_rw_dst_asm_prog_load(test, SERV6_REWRITE_IP);

}



static int sendmsg6_rw_v4mapped_prog_load(const struct sock_addr_test *test)

{

	return sendmsg6_rw_dst_asm_prog_load(test, SERV6_V4MAPPED_IP);

}



static int sendmsg6_rw_c_prog_load(const struct sock_addr_test *test)

{

	return load_path(test, SENDMSG6_PROG_PATH);

}



static int cmp_addr(const struct sockaddr_storage *addr1,

		    const struct sockaddr_storage *addr2, int cmp_port)

{
@@ -656,6 +968,135 @@ static int connect_to_server(int type, const struct sockaddr_storage *addr, 
	return fd;

}



int init_pktinfo(int domain, struct cmsghdr *cmsg)

{

	struct in6_pktinfo *pktinfo6;

	struct in_pktinfo *pktinfo4;



	if (domain == AF_INET) {

		cmsg->cmsg_level = SOL_IP;

		cmsg->cmsg_type = IP_PKTINFO;

		cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));

		pktinfo4 = (struct in_pktinfo *)CMSG_DATA(cmsg);

		memset(pktinfo4, 0, sizeof(struct in_pktinfo));

		if (inet_pton(domain, SRC4_IP,

			      (void *)&pktinfo4->ipi_spec_dst) != 1)

			return -1;

	} else if (domain == AF_INET6) {

		cmsg->cmsg_level = SOL_IPV6;

		cmsg->cmsg_type = IPV6_PKTINFO;

		cmsg->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));

		pktinfo6 = (struct in6_pktinfo *)CMSG_DATA(cmsg);

		memset(pktinfo6, 0, sizeof(struct in6_pktinfo));

		if (inet_pton(domain, SRC6_IP,

			      (void *)&pktinfo6->ipi6_addr) != 1)

			return -1;

	} else {

		return -1;

	}



	return 0;

}



static int sendmsg_to_server(const struct sockaddr_storage *addr,

			     socklen_t addr_len, int set_cmsg, int *syscall_err)

{

	union {

		char buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];

		struct cmsghdr align;

	} control6;

	union {

		char buf[CMSG_SPACE(sizeof(struct in_pktinfo))];

		struct cmsghdr align;

	} control4;

	struct msghdr hdr;

	struct iovec iov;

	char data = 'a';

	int domain;

	int fd = -1;



	domain = addr->ss_family;



	if (domain != AF_INET && domain != AF_INET6) {

		log_err("Unsupported address family");

		goto err;

	}



	fd = socket(domain, SOCK_DGRAM, 0);

	if (fd == -1) {

		log_err("Failed to create client socket");

		goto err;

	}



	memset(&iov, 0, sizeof(iov));

	iov.iov_base = &data;

	iov.iov_len = sizeof(data);



	memset(&hdr, 0, sizeof(hdr));

	hdr.msg_name = (void *)addr;

	hdr.msg_namelen = addr_len;

	hdr.msg_iov = &iov;

	hdr.msg_iovlen = 1;



	if (set_cmsg) {

		if (domain == AF_INET) {

			hdr.msg_control = &control4;

			hdr.msg_controllen = sizeof(control4.buf);

		} else if (domain == AF_INET6) {

			hdr.msg_control = &control6;

			hdr.msg_controllen = sizeof(control6.buf);

		}

		if (init_pktinfo(domain, CMSG_FIRSTHDR(&hdr))) {

			log_err("Fail to init pktinfo");

			goto err;

		}

	}



	if (sendmsg(fd, &hdr, 0) != sizeof(data)) {

		log_err("Fail to send message to server");

		*syscall_err = errno;

		goto err;

	}



	goto out;

err:

	close(fd);

	fd = -1;

out:

	return fd;

}



static int recvmsg_from_client(int sockfd, struct sockaddr_storage *src_addr)

{

	struct timeval tv;

	struct msghdr hdr;

	struct iovec iov;

	char data[64];

	fd_set rfds;



	FD_ZERO(&rfds);

	FD_SET(sockfd, &rfds);



	tv.tv_sec = 2;

	tv.tv_usec = 0;



	if (select(sockfd + 1, &rfds, NULL, NULL, &tv) <= 0 ||

	    !FD_ISSET(sockfd, &rfds))

		return -1;



	memset(&iov, 0, sizeof(iov));

	iov.iov_base = data;

	iov.iov_len = sizeof(data);



	memset(&hdr, 0, sizeof(hdr));

	hdr.msg_name = src_addr;

	hdr.msg_namelen = sizeof(struct sockaddr_storage);

	hdr.msg_iov = &iov;

	hdr.msg_iovlen = 1;



	return recvmsg(sockfd, &hdr, 0);

}



static int init_addrs(const struct sock_addr_test *test,

		      struct sockaddr_storage *requested_addr,

		      struct sockaddr_storage *expected_addr,
@@ -753,6 +1194,69 @@ static int run_connect_test_case(const struct sock_addr_test *test) 
	return err;

}



static int run_sendmsg_test_case(const struct sock_addr_test *test)

{

	socklen_t addr_len = sizeof(struct sockaddr_storage);

	struct sockaddr_storage expected_src_addr;

	struct sockaddr_storage requested_addr;

	struct sockaddr_storage expected_addr;

	struct sockaddr_storage real_src_addr;

	int clientfd = -1;

	int servfd = -1;

	int set_cmsg;

	int err = 0;



	if (test->type != SOCK_DGRAM)

		goto err;



	if (init_addrs(test, &requested_addr, &expected_addr,

		       &expected_src_addr))

		goto err;



	/* Prepare server to sendmsg to */

	servfd = start_server(test->type, &expected_addr, addr_len);

	if (servfd == -1)

		goto err;



	for (set_cmsg = 0; set_cmsg <= 1; ++set_cmsg) {

		if (clientfd >= 0)

			close(clientfd);



		clientfd = sendmsg_to_server(&requested_addr, addr_len,

					     set_cmsg, &err);

		if (err)

			goto out;

		else if (clientfd == -1)

			goto err;



		/* Try to receive message on server instead of using

		 * getpeername(2) on client socket, to check that client's

		 * destination address was rewritten properly, since

		 * getpeername(2) doesn't work with unconnected datagram

		 * sockets.

		 *

		 * Get source address from recvmsg(2) as well to make sure

		 * source was rewritten properly: getsockname(2) can't be used

		 * since socket is unconnected and source defined for one

		 * specific packet may differ from the one used by default and

		 * returned by getsockname(2).

		 */

		if (recvmsg_from_client(servfd, &real_src_addr) == -1)

			goto err;



		if (cmp_addr(&real_src_addr, &expected_src_addr, /*cmp_port*/0))

			goto err;

	}



	goto out;

err:

	err = -1;

out:

	close(clientfd);

	close(servfd);

	return err;

}



static int run_test_case(int cgfd, const struct sock_addr_test *test)

{

	int progfd = -1;
@@ -784,10 +1288,24 @@ static int run_test_case(int cgfd, const struct sock_addr_test *test) 
	case BPF_CGROUP_INET6_CONNECT:

		err = run_connect_test_case(test);

		break;

	case BPF_CGROUP_UDP4_SENDMSG:

	case BPF_CGROUP_UDP6_SENDMSG:

		err = run_sendmsg_test_case(test);

		break;

	default:

		goto err;

	}



	if (test->expected_result == SYSCALL_EPERM && err == EPERM) {

		err = 0; /* error was expected, reset it */

		goto out;

	}



	if (test->expected_result == SYSCALL_ENOTSUPP && err == ENOTSUPP) {

		err = 0; /* error was expected, reset it */

		goto out;

	}



	if (err || test->expected_result != SUCCESS)

		goto err;