context.c revision 412e5c62115e881cce79921e2467c6c0990a0a8a
/*
* Copyright (C) 2000 Internet Software Consortium.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*/
#include <config.h>
#include <fcntl.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <lwres/lwres.h>
#include "context_p.h"
#include "assert_p.h"
/*
* Some systems define the socket length argument as an int, some as size_t,
* some as socklen_t. The last is what the current POSIX standard mandates.
* This definition is here so it can be portable but easily changed if needed.
*/
#ifndef LWRES_SOCKADDR_LEN_T
#define LWRES_SOCKADDR_LEN_T unsigned int
#endif
lwres_uint16_t lwres_udp_port = LWRES_UDP_PORT;
static void *
lwres_malloc(void *, size_t);
static void
lwres_free(void *, void *, size_t);
static lwres_result_t
context_connect(lwres_context_t *);
lwres_result_t
lwres_context_create(lwres_context_t **contextp, void *arg,
lwres_malloc_t malloc_function,
lwres_free_t free_function,
unsigned int flags)
{
lwres_context_t *ctx;
REQUIRE(contextp != NULL && *contextp == NULL);
/*
* If we were not given anything special to use, use our own
* functions. These are just wrappers around malloc() and free().
*/
if (malloc_function == NULL || free_function == NULL) {
REQUIRE(malloc_function == NULL);
REQUIRE(free_function == NULL);
malloc_function = lwres_malloc;
free_function = lwres_free;
}
ctx = malloc_function(arg, sizeof(lwres_context_t));
if (ctx == NULL)
return (LWRES_R_NOMEMORY);
/*
* Set up the context.
*/
ctx->malloc = malloc_function;
ctx->free = free_function;
ctx->arg = arg;
ctx->sock = -1;
ctx->timeout = LWRES_DEFAULT_TIMEOUT;
ctx->serial = (lwres_uint32_t)ctx; /* XXXMLG */
if ((flags & LWRES_CONTEXT_SERVERMODE) == 0)
(void)context_connect(ctx); /* XXXMLG */
/*
* Init resolv.conf bits.
*/
lwres_conf_init(ctx);
*contextp = ctx;
return (LWRES_R_SUCCESS);
}
void
lwres_context_destroy(lwres_context_t **contextp) {
lwres_context_t *ctx;
REQUIRE(contextp != NULL && *contextp != NULL);
ctx = *contextp;
*contextp = NULL;
if (ctx->sock != -1) {
close(ctx->sock);
ctx->sock = -1;
}
CTXFREE(ctx, sizeof(lwres_context_t));
}
lwres_uint32_t
lwres_context_nextserial(lwres_context_t *ctx) {
REQUIRE(ctx != NULL);
return (ctx->serial++);
}
void
lwres_context_initserial(lwres_context_t *ctx, lwres_uint32_t serial) {
REQUIRE(ctx != NULL);
ctx->serial = serial;
}
void
lwres_context_freemem(lwres_context_t *ctx, void *mem, size_t len) {
REQUIRE(mem != NULL);
REQUIRE(len != 0);
CTXFREE(mem, len);
}
void *
lwres_context_allocmem(lwres_context_t *ctx, size_t len) {
REQUIRE(len != 0);
return (CTXMALLOC(len));
}
static void *
lwres_malloc(void *arg, size_t len) {
void *mem;
(void)arg;
mem = malloc(len);
if (mem == NULL)
return (NULL);
memset(mem, 0xe5, len);
return (mem);
}
static void
lwres_free(void *arg, void *mem, size_t len) {
(void)arg;
memset(mem, 0xa9, len);
free(mem);
}
static lwres_result_t
context_connect(lwres_context_t *ctx) {
int s;
int ret;
struct sockaddr_in localhost;
memset(&localhost, 0, sizeof(localhost));
localhost.sin_family = AF_INET;
localhost.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
localhost.sin_port = htons(lwres_udp_port);
s = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (s < 0)
return (LWRES_R_IOERROR);
ret = connect(s, (struct sockaddr *)&localhost, sizeof(localhost));
if (ret != 0) {
close(s);
return (LWRES_R_IOERROR);
}
ctx->sock = s;
return (LWRES_R_SUCCESS);
}
lwres_result_t
lwres_context_sendrecv(lwres_context_t *ctx,
void *sendbase, int sendlen,
void *recvbase, int recvlen,
int *recvd_len)
{
int ret;
int ret2;
int flags;
struct sockaddr_in sin;
LWRES_SOCKADDR_LEN_T fromlen;
fd_set readfds;
struct timeval timeout;
/*
* Type of tv_sec is long, so make sure the unsigned long timeout
* does not overflow it.
*/
if (ctx->timeout <= LONG_MAX)
timeout.tv_sec = (long)ctx->timeout;
else
timeout.tv_sec = LONG_MAX;
timeout.tv_usec = 0;
ret = sendto(ctx->sock, sendbase, sendlen, 0, NULL, 0);
if (ret < 0)
return (LWRES_R_IOERROR);
if (ret != sendlen)
return (LWRES_R_IOERROR);
again:
flags = fcntl(ctx->sock, F_GETFL, 0);
flags |= O_NONBLOCK;
ret = fcntl(ctx->sock, F_SETFL, flags);
if (ret < 0)
return (LWRES_R_IOERROR);
FD_ZERO(&readfds);
FD_SET(ctx->sock, &readfds);
ret2 = select(ctx->sock + 1, &readfds, NULL, NULL, &timeout);
flags = fcntl(ctx->sock, F_GETFL, 0);
flags &= ~O_NONBLOCK;
ret = fcntl(ctx->sock, F_SETFL, flags);
if (ret < 0)
return (LWRES_R_IOERROR);
/*
* What happened with select?
*/
if (ret2 < 0)
return (LWRES_R_IOERROR);
if (ret2 == 0)
return (LWRES_R_TIMEOUT);
fromlen = sizeof(sin);
/*
* The address of fromlen is cast to void * to shut up compiler
* warnings, namely on systems that have the sixth parameter
* prototyped as a signed int when LWRES_SOCKADDR_LEN_T is
* defined as unsigned.
*/
ret = recvfrom(ctx->sock, recvbase, recvlen, 0,
(struct sockaddr *)&sin, (void *)&fromlen);
if (ret < 0)
return (LWRES_R_IOERROR);
/*
* If we got something other than what we expect, re-issue our
* recvfrom() call. This can happen if an old result comes in,
* or if someone is sending us random stuff.
*/
if (sin.sin_addr.s_addr != htonl(INADDR_LOOPBACK)
|| sin.sin_port != htons(lwres_udp_port))
goto again;
if (recvd_len != NULL)
*recvd_len = ret;
return (LWRES_R_SUCCESS);
}