Implement IPPROTO_IP control messages decoding

* net.c: Include "xlat/ip_cmsg_types.h".
(print_cmsg_ip_pktinfo, print_cmsg_ip_ttl, print_cmsg_ip_tos,
print_cmsg_ip_opts, print_cmsg_ip_recverr, print_cmsg_ip_checksum,
print_cmsg_ip_origdstaddr): New functions.
(print_cmsg_type_data): Add generic SOL_IP level decoding.
Use these functions for decoding of IP_PKTINFO, IP_TTL, IP_TOS,
IP_RECVOPTS, IP_RETOPTS, IP_RECVERR, IP_ORIGDSTADDR, IP_CHECKSUM,
and SCM_SECURITY type messages.
* xlat/ip_cmsg_types.in: New file.
* xlat/sockipoptions.in: Move IP_RETOPTS before IP_RECVRETOPTS.
* tests/inet-cmsg.c: New file.
* tests/inet-cmsg.test: New test.
* tests/Makefile.am (check_PROGRAMS): Add inet-cmsg.
(TESTS): Add inet-cmsg.test.
* tests/.gitignore: Add inet-cmsg.

Suggested-by: Orion Poplawski <orion@cora.nwra.com>

net.c

@@ -302,6 +302,7 @@ printsock(struct tcb *tcp, long addr, int addrlen)
 }
 
 #include "xlat/scmvals.h"
+#include "xlat/ip_cmsg_types.h"
 
 #if SUPPORTED_PERSONALITIES > 1 && SIZEOF_LONG > 4
 struct cmsghdr32 {
@@ -365,6 +366,111 @@ print_scm_security(struct tcb *tcp, const void *cmsg_data,
 	print_quoted_string(cmsg_data, data_len, 0);
 }
 
+static void
+print_cmsg_ip_pktinfo(struct tcb *tcp, const void *cmsg_data,
+		      const size_t data_len)
+{
+	const struct in_pktinfo *info = cmsg_data;
+
+	if (sizeof(*info) > data_len)
+		return;
+
+	tprints(", {ipi_ifindex=");
+	print_ifindex(info->ipi_ifindex);
+	tprintf(", ipi_spec_dst=inet_addr(\"%s\"), ipi_addr=inet_addr(\"%s\")}",
+		inet_ntoa(info->ipi_spec_dst), inet_ntoa(info->ipi_addr));
+}
+
+static void
+print_cmsg_ip_ttl(struct tcb *tcp, const void *cmsg_data,
+		  const size_t data_len)
+{
+	const unsigned int *ttl = cmsg_data;
+
+	if (sizeof(*ttl) > data_len)
+		return;
+
+	tprintf(", {ttl=%u}", *ttl);
+}
+
+static void
+print_cmsg_ip_tos(struct tcb *tcp, const void *cmsg_data,
+		  const size_t data_len)
+{
+	const uint8_t *tos = cmsg_data;
+
+	if (sizeof(*tos) > data_len)
+		return;
+
+	tprintf(", {tos=%x}", *tos);
+}
+
+static void
+print_cmsg_ip_checksum(struct tcb *tcp, const void *cmsg_data,
+		       const size_t data_len)
+{
+	const uint32_t *csum = cmsg_data;
+
+	if (sizeof(*csum) > data_len)
+		return;
+
+	tprintf(", {csum=%u}", *csum);
+}
+
+static void
+print_cmsg_ip_opts(struct tcb *tcp, const void *cmsg_data,
+		   const size_t data_len)
+{
+	const char *opts = cmsg_data;
+	size_t i;
+
+	if (!data_len)
+		return;
+
+	tprints(", {opts=0x");
+	for (i = 0; i < data_len; ++i)
+		tprintf("%02x", opts[i]);
+	tprints("}");
+}
+
+static void
+print_cmsg_ip_recverr(struct tcb *tcp, const void *cmsg_data,
+		      const size_t data_len)
+{
+	const struct {
+		uint32_t ee_errno;
+		uint8_t  ee_origin;
+		uint8_t  ee_type;
+		uint8_t  ee_code;
+		uint8_t  ee_pad;
+		uint32_t ee_info;
+		uint32_t ee_data;
+		struct sockaddr_in offender;
+	} *err = cmsg_data;
+
+	if (sizeof(*err) > data_len)
+		return;
+
+	tprintf(", {ee_errno=%u, ee_origin=%u, ee_type=%u, ee_code=%u"
+		", ee_info=%u, ee_data=%u, offender=",
+		err->ee_errno, err->ee_origin, err->ee_type,
+		err->ee_code, err->ee_info, err->ee_data);
+	print_sockaddr(tcp, (const void *) &err->offender,
+		sizeof(err->offender));
+	tprints("}");
+}
+
+static void
+print_cmsg_ip_origdstaddr(struct tcb *tcp, const void *cmsg_data,
+			  const size_t data_len)
+{
+	if (sizeof(struct sockaddr_in) > data_len)
+		return;
+
+	tprints(", ");
+	print_sockaddr(tcp, cmsg_data, data_len);
+}
+
 static void
 print_cmsg_type_data(struct tcb *tcp, const int cmsg_level, const int cmsg_type,
 		     const void *cmsg_data, const size_t data_len)
@@ -384,6 +490,36 @@ print_cmsg_type_data(struct tcb *tcp, const int cmsg_level, const int cmsg_type,
 			break;
 		}
 		break;
+	case SOL_IP:
+		printxval(ip_cmsg_types, cmsg_type, "IP_???");
+		switch (cmsg_type) {
+		case IP_PKTINFO:
+			print_cmsg_ip_pktinfo(tcp, cmsg_data, data_len);
+			break;
+		case IP_TTL:
+			print_cmsg_ip_ttl(tcp, cmsg_data, data_len);
+			break;
+		case IP_TOS:
+			print_cmsg_ip_tos(tcp, cmsg_data, data_len);
+			break;
+		case IP_RECVOPTS:
+		case IP_RETOPTS:
+			print_cmsg_ip_opts(tcp, cmsg_data, data_len);
+			break;
+		case IP_RECVERR:
+			print_cmsg_ip_recverr(tcp, cmsg_data, data_len);
+			break;
+		case IP_ORIGDSTADDR:
+			print_cmsg_ip_origdstaddr(tcp, cmsg_data, data_len);
+			break;
+		case IP_CHECKSUM:
+			print_cmsg_ip_checksum(tcp, cmsg_data, data_len);
+			break;
+		case SCM_SECURITY:
+			print_scm_security(tcp, cmsg_data, data_len);
+			break;
+		}
+		break;
 	default:
 		tprintf("%u", cmsg_type);
 	}

tests/.gitignore

@@ -14,6 +14,7 @@ getdents
 getdents64
 getrandom
 inet-accept-connect-send-recv
+inet-cmsg
 ioctl
 ip_mreq
 ipc_msg

tests/Makefile.am

@@ -27,6 +27,7 @@ check_PROGRAMS = \
 	getdents64 \
 	getrandom \
 	inet-accept-connect-send-recv \
+	inet-cmsg \
 	ioctl \
 	ip_mreq \
 	ipc_msg \
@@ -125,6 +126,7 @@ TESTS = \
 	getdents.test \
 	getdents64.test \
 	getrandom.test \
+	inet-cmsg.test \
 	ioctl.test \
 	ip_mreq.test \
 	ipc_msg.test \

tests/inet-cmsg.c

@@ -0,0 +1,192 @@
+/*
+ * Copyright (c) 2015 Dmitry V. Levin <ldv@altlinux.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+static void
+print_pktinfo(const struct cmsghdr *c)
+{
+	printf("IP_PKTINFO, {ipi_ifindex=if_nametoindex(\"lo\")"
+	       ", ipi_spec_dst=inet_addr(\"127.0.0.1\")"
+	       ", ipi_addr=inet_addr(\"127.0.0.1\")}");
+}
+
+static void
+print_ttl(const struct cmsghdr *c)
+{
+	const unsigned int *ttl = (const unsigned int *) CMSG_DATA(c);
+
+	printf("IP_TTL, {ttl=%u}", *ttl);
+}
+
+static void
+print_tos(const struct cmsghdr *c)
+{
+	const uint8_t *tos = (const uint8_t *) CMSG_DATA(c);
+
+	printf("IP_TOS, {tos=%x}", *tos);
+}
+
+static void
+print_opts(const char *name, const struct cmsghdr *c)
+{
+	const unsigned char *opts = (const unsigned char *) CMSG_DATA(c);
+	const size_t len = c->cmsg_len - CMSG_ALIGN(sizeof(*c));
+
+	printf("%s", name);
+	if (len) {
+		printf(", {opts=0x");
+		size_t i;
+		for (i = 0; i < len; ++i)
+			printf("%02x", opts[i]);
+		printf("}");
+	}
+}
+
+static void
+print_origdstaddr(const struct cmsghdr *c)
+{
+	const struct sockaddr_in *sin =
+		(const struct sockaddr_in *) CMSG_DATA(c);
+
+	printf("IP_ORIGDSTADDR, {sa_family=AF_INET, sin_port=htons(%u)"
+	       ", sin_addr=inet_addr(\"127.0.0.1\")}", ntohs(sin->sin_port));
+}
+
+int
+main(void)
+{
+	int i;
+	while ((i = open("/dev/null", O_RDWR)) < 3)
+		assert(i >= 0);
+	assert(!close(0));
+	assert(!close(3));
+
+	if (socket(PF_INET, SOCK_DGRAM, 0)) {
+		perror("socket");
+		return 77;
+	}
+	struct sockaddr_in addr = {
+		.sin_family = AF_INET,
+		.sin_addr.s_addr = htonl(INADDR_LOOPBACK)
+	};
+	socklen_t len = sizeof(addr);
+	assert(!bind(0, (struct sockaddr *) &addr, len));
+	assert(!getsockname(0, (struct sockaddr *) &addr, &len));
+
+	assert(socket(PF_INET, SOCK_DGRAM, 0) == 3);
+	assert(!connect(3, (struct sockaddr *) &addr, len));
+
+	const int opt_1 = htonl(0x01000000);
+#define SETSOCKOPT(fd, name) assert(!setsockopt(fd, IPPROTO_IP, (name), &opt_1, sizeof(opt_1)))
+	SETSOCKOPT(3, IP_OPTIONS);
+	SETSOCKOPT(0, IP_PKTINFO);
+	SETSOCKOPT(0, IP_RECVTTL);
+	SETSOCKOPT(0, IP_RECVTOS);
+	SETSOCKOPT(0, IP_RECVOPTS);
+	SETSOCKOPT(0, IP_RETOPTS);
+#ifdef IP_RECVORIGDSTADDR
+	SETSOCKOPT(0, IP_RECVORIGDSTADDR);
+#endif
+
+	static const char data[] = "data";
+	const size_t size = sizeof(data) - 1;
+	assert(send(3, data, size, 0) == (int) size);
+	assert(!close(3));
+
+	char buf[size];
+	struct iovec iov = {
+		.iov_base = buf,
+		.iov_len = sizeof(buf)
+	};
+	struct cmsghdr control[16];
+	struct msghdr mh = {
+		.msg_name = &addr,
+		.msg_namelen = len,
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+		.msg_control = control,
+		.msg_controllen = sizeof(control)
+	};
+
+	assert(recvmsg(0, &mh, 0) == (int) size);
+	assert(!close(0));
+
+	printf("recvmsg(0, {msg_name(%u)={sa_family=AF_INET, sin_port=htons(%u)"
+	       ", sin_addr=inet_addr(\"127.0.0.1\")}, msg_iov(1)=[{\"%s\", %zu}]"
+	       ", msg_controllen=%zu, [",
+	       (unsigned) mh.msg_namelen, ntohs(addr.sin_port),
+	       data, size, mh.msg_controllen);
+
+	struct cmsghdr *c;
+	for (c = CMSG_FIRSTHDR(&mh); c; c = CMSG_NXTHDR(&mh, c)) {
+		if (IPPROTO_IP != c->cmsg_level)
+			continue;
+		if (c != control)
+			printf(", ");
+		printf("{cmsg_len=%zu, cmsg_level=SOL_IP, cmsg_type=",
+		       c->cmsg_len);
+		switch (c->cmsg_type) {
+			case IP_PKTINFO:
+				print_pktinfo(c);
+				break;
+			case IP_TTL:
+				print_ttl(c);
+				break;
+			case IP_TOS:
+				print_tos(c);
+				break;
+			case IP_RECVOPTS:
+				print_opts("IP_RECVOPTS", c);
+				break;
+			case IP_RETOPTS:
+				print_opts("IP_RETOPTS", c);
+				break;
+#ifdef IP_ORIGDSTADDR
+			case IP_ORIGDSTADDR:
+				print_origdstaddr(c);
+				break;
+#endif
+			default:
+				printf("%d", c->cmsg_type);
+				break;
+		}
+		printf("}");
+	}
+	printf("], msg_flags=0}, 0) = %zu\n", size);
+	puts("+++ exited with 0 +++");
+
+	return 0;
+}

tests/inet-cmsg.test

@@ -0,0 +1,15 @@
+#!/bin/sh
+
+# Check IPPROTO_IP control messages decoding.
+
+. "${srcdir=.}/init.sh"
+
+run_prog > /dev/null
+
+OUT="$LOG.out"
+run_strace -erecvmsg $args > "$OUT"
+
+match_diff "$OUT" "$LOG"
+rm -f "$OUT"
+
+exit 0

xlat/ip_cmsg_types.in

@@ -0,0 +1,9 @@
+IP_TOS		1
+IP_TTL		2
+IP_RECVOPTS	6
+IP_RETOPTS	7
+IP_PKTINFO	8
+IP_RECVERR	11
+IP_ORIGDSTADDR	20
+IP_CHECKSUM	23
+SCM_SECURITY

xlat/sockipoptions.in

@@ -5,9 +5,9 @@ IP_OPTIONS
 IP_ROUTER_ALERT
 IP_RECVOPTIONS
 IP_RECVOPTS
+IP_RETOPTS
 IP_RECVRETOPTS
 IP_RECVDSTADDR
-IP_RETOPTS
 IP_PKTINFO
 IP_PKTOPTIONS
 IP_MTU_DISCOVER