strace/socketutils.c
Dmitry V. Levin 3c17d1b5e1 Implement caching of print_sockaddr_by_inode
As -yy parser, compared to -y, needs to do at least 5 extra syscalls
(getxattr, socket, sendmsg, recvmsg, close) to print socket details,
caching results of netlink conversations between strace and kernel
noticeably reduces amount of system time spent by strace.

The caching is safe since sockets do not change their addresses after
successful bind or connect syscall.

* defs.h (string_quote, print_sockaddr_by_inode_cached): New prototypes.
* socketutils.c (cache_entry): New type.
(CACHE_SIZE, CACHE_MASK): New macros.
(cache): New static array.
(cache_and_print_inode_details): New static function.
(print_sockaddr_by_inode_cached): New function.
(inet_parse_response, unix_parse_response): Use
cache_and_print_inode_details.
* util.c (printfd): Use string_quote and print_sockaddr_by_inode_cached.
(string_quote): Remove static qualifier.
* NEWS: Mention this improvement.
* tests/unix-yy.c (main): Update.
2016-02-03 12:43:22 +00:00

413 lines
10 KiB
C

/*
* Copyright (c) 2014 Zubin Mithra <zubin.mithra@gmail.com>
* Copyright (c) 2014-2016 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 "defs.h"
#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <linux/netlink.h>
#include <linux/sock_diag.h>
#include <linux/inet_diag.h>
#include <linux/unix_diag.h>
#include <linux/rtnetlink.h>
#if !defined NETLINK_SOCK_DIAG && defined NETLINK_INET_DIAG
# define NETLINK_SOCK_DIAG NETLINK_INET_DIAG
#endif
#include <sys/un.h>
#ifndef UNIX_PATH_MAX
# define UNIX_PATH_MAX sizeof(((struct sockaddr_un *) 0)->sun_path)
#endif
typedef struct {
unsigned long inode;
char *details;
} cache_entry;
#define CACHE_SIZE 1024U
static cache_entry cache[CACHE_SIZE];
#define CACHE_MASK (CACHE_SIZE - 1)
static int
cache_and_print_inode_details(const unsigned long inode, char *details)
{
cache_entry *e = &cache[inode & CACHE_MASK];
free(e->details);
e->inode = inode;
e->details = details;
tprints(details);
return 1;
}
bool
print_sockaddr_by_inode_cached(const unsigned long inode)
{
const cache_entry *e = &cache[inode & CACHE_MASK];
if (e && inode == e->inode) {
tprints(e->details);
return true;
}
return false;
}
static bool
inet_send_query(const int fd, const int family, const int proto)
{
struct sockaddr_nl nladdr = {
.nl_family = AF_NETLINK
};
struct {
struct nlmsghdr nlh;
struct inet_diag_req_v2 idr;
} req = {
.nlh = {
.nlmsg_len = sizeof(req),
.nlmsg_type = SOCK_DIAG_BY_FAMILY,
.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST
},
.idr = {
.sdiag_family = family,
.sdiag_protocol = proto,
.idiag_states = -1
}
};
struct iovec iov = {
.iov_base = &req,
.iov_len = sizeof(req)
};
struct msghdr msg = {
.msg_name = (void *) &nladdr,
.msg_namelen = sizeof(nladdr),
.msg_iov = &iov,
.msg_iovlen = 1
};
for (;;) {
if (sendmsg(fd, &msg, 0) < 0) {
if (errno == EINTR)
continue;
return false;
}
return true;
}
}
static int
inet_parse_response(const char *proto_name, const void *data,
const int data_len, const unsigned long inode)
{
const struct inet_diag_msg *diag_msg = data;
static const char zero_addr[sizeof(struct in6_addr)];
socklen_t addr_size, text_size;
if (data_len < (int) NLMSG_LENGTH(sizeof(*diag_msg)))
return -1;
if (diag_msg->idiag_inode != inode)
return 0;
switch(diag_msg->idiag_family) {
case AF_INET:
addr_size = sizeof(struct in_addr);
text_size = INET_ADDRSTRLEN;
break;
case AF_INET6:
addr_size = sizeof(struct in6_addr);
text_size = INET6_ADDRSTRLEN;
break;
default:
return -1;
}
char src_buf[text_size];
char *details;
if (!inet_ntop(diag_msg->idiag_family, diag_msg->id.idiag_src,
src_buf, text_size))
return -1;
if (diag_msg->id.idiag_dport ||
memcmp(zero_addr, diag_msg->id.idiag_dst, addr_size)) {
char dst_buf[text_size];
if (!inet_ntop(diag_msg->idiag_family, diag_msg->id.idiag_dst,
dst_buf, text_size))
return -1;
if (asprintf(&details, "%s:[%s:%u->%s:%u]", proto_name,
src_buf, ntohs(diag_msg->id.idiag_sport),
dst_buf, ntohs(diag_msg->id.idiag_dport)) < 0)
return false;
} else {
if (asprintf(&details, "%s:[%s:%u]", proto_name, src_buf,
ntohs(diag_msg->id.idiag_sport)) < 0)
return false;
}
return cache_and_print_inode_details(inode, details);
}
static bool
receive_responses(const int fd, const unsigned long inode,
const char *proto_name,
int (* parser) (const char *, const void *,
int, unsigned long))
{
static long buf[8192 / sizeof(long)];
struct sockaddr_nl nladdr = {
.nl_family = AF_NETLINK
};
struct iovec iov = {
.iov_base = buf,
.iov_len = sizeof(buf)
};
int flags = 0;
for (;;) {
ssize_t ret;
struct msghdr msg = {
.msg_name = (void *) &nladdr,
.msg_namelen = sizeof(nladdr),
.msg_iov = &iov,
.msg_iovlen = 1
};
ret = recvmsg(fd, &msg, flags);
if (ret < 0) {
if (errno == EINTR)
continue;
return false;
}
struct nlmsghdr *h = (struct nlmsghdr *) buf;
if (!NLMSG_OK(h, ret))
return false;
for (; NLMSG_OK(h, ret); h = NLMSG_NEXT(h, ret)) {
if (h->nlmsg_type != SOCK_DIAG_BY_FAMILY)
return false;
int rc = parser(proto_name, NLMSG_DATA(h),
h->nlmsg_len, inode);
if (rc > 0)
return true;
if (rc < 0)
return false;
}
flags = MSG_DONTWAIT;
}
}
static bool
inet_print(const int fd, const int family, const int protocol,
const unsigned long inode, const char *proto_name)
{
return inet_send_query(fd, family, protocol)
&& receive_responses(fd, inode, proto_name, inet_parse_response);
}
static bool
unix_send_query(const int fd, const unsigned long inode)
{
struct sockaddr_nl nladdr = {
.nl_family = AF_NETLINK
};
struct {
struct nlmsghdr nlh;
struct unix_diag_req udr;
} req = {
.nlh = {
.nlmsg_len = sizeof(req),
.nlmsg_type = SOCK_DIAG_BY_FAMILY,
.nlmsg_flags = NLM_F_REQUEST
},
.udr = {
.sdiag_family = AF_UNIX,
.udiag_ino = inode,
.udiag_states = -1,
.udiag_show = UDIAG_SHOW_NAME | UDIAG_SHOW_PEER,
.udiag_cookie = { ~0U, ~0U }
}
};
struct iovec iov = {
.iov_base = &req,
.iov_len = sizeof(req)
};
struct msghdr msg = {
.msg_name = (void *) &nladdr,
.msg_namelen = sizeof(nladdr),
.msg_iov = &iov,
.msg_iovlen = 1
};
for (;;) {
if (sendmsg(fd, &msg, 0) < 0) {
if (errno == EINTR)
continue;
return false;
}
return true;
}
}
static int
unix_parse_response(const char *proto_name, const void *data,
const int data_len, const unsigned long inode)
{
const struct unix_diag_msg *diag_msg = data;
struct rtattr *attr;
int rta_len = data_len - NLMSG_LENGTH(sizeof(*diag_msg));
uint32_t peer = 0;
size_t path_len = 0;
char path[UNIX_PATH_MAX + 1];
if (rta_len < 0)
return -1;
if (diag_msg->udiag_ino != inode)
return 0;
if (diag_msg->udiag_family != AF_UNIX)
return -1;
for (attr = (struct rtattr *) (diag_msg + 1);
RTA_OK(attr, rta_len);
attr = RTA_NEXT(attr, rta_len)) {
switch (attr->rta_type) {
case UNIX_DIAG_NAME:
if (!path_len) {
path_len = RTA_PAYLOAD(attr);
if (path_len > UNIX_PATH_MAX)
path_len = UNIX_PATH_MAX;
memcpy(path, RTA_DATA(attr), path_len);
path[path_len] = '\0';
}
break;
case UNIX_DIAG_PEER:
if (RTA_PAYLOAD(attr) >= 4)
peer = *(uint32_t *) RTA_DATA(attr);
break;
}
}
/*
* print obtained information in the following format:
* "UNIX:[" SELF_INODE [ "->" PEER_INODE ][ "," SOCKET_FILE ] "]"
*/
if (!peer && !path_len)
return -1;
char peer_str[3 + sizeof(peer) * 3];
if (peer)
snprintf(peer_str, sizeof(peer_str), "->%u", peer);
else
peer_str[0] = '\0';
const char *path_str;
if (path_len) {
char *outstr = alloca(4 * path_len + 4);
outstr[0] = ',';
if (path[0] == '\0') {
outstr[1] = '@';
string_quote(path + 1, outstr + 2,
path_len - 1, QUOTE_0_TERMINATED);
} else {
string_quote(path, outstr + 1,
path_len, QUOTE_0_TERMINATED);
}
path_str = outstr;
} else {
path_str = "";
}
char *details;
if (asprintf(&details, "%s:[%lu%s%s]", proto_name, inode,
peer_str, path_str) < 0)
return -1;
return cache_and_print_inode_details(inode, details);
}
static bool
unix_print(int fd, const unsigned long inode)
{
return unix_send_query(fd, inode)
&& receive_responses(fd, inode, "UNIX", unix_parse_response);
}
/* Given an inode number of a socket, print out the details
* of the ip address and port. */
bool
print_sockaddr_by_inode(const unsigned long inode, const char *proto_name)
{
int fd;
bool r = false;
fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_SOCK_DIAG);
if (fd < 0)
return false;
if (proto_name) {
if (strcmp(proto_name, "TCP") == 0)
r = inet_print(fd, AF_INET, IPPROTO_TCP, inode, "TCP");
else if (strcmp(proto_name, "UDP") == 0)
r = inet_print(fd, AF_INET, IPPROTO_UDP, inode, "UDP");
else if (strcmp(proto_name, "TCPv6") == 0)
r = inet_print(fd, AF_INET6, IPPROTO_TCP, inode, "TCPv6");
else if (strcmp(proto_name, "UDPv6") == 0)
r = inet_print(fd, AF_INET6, IPPROTO_UDP, inode, "UDPv6");
else if (strcmp(proto_name, "UNIX") == 0)
r = unix_print(fd, inode);
if (!r) {
tprintf("%s:[%lu]", proto_name, inode);
r = true;
}
} else {
const struct {
const int family;
const int protocol;
const char *name;
} protocols[] = {
{ AF_INET, IPPROTO_TCP, "TCP" },
{ AF_INET, IPPROTO_UDP, "UDP" },
{ AF_INET6, IPPROTO_TCP, "TCPv6" },
{ AF_INET6, IPPROTO_UDP, "UDPv6" }
};
size_t i;
for (i = 0; i < ARRAY_SIZE(protocols); ++i) {
if ((r = inet_print(fd, protocols[i].family,
protocols[i].protocol, inode,
protocols[i].name)))
break;
}
}
close(fd);
return r;
}