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/*
* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
*
* SPDX-License-Identifier: MPL-2.0
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, you can obtain one at https://mozilla.org/MPL/2.0/.
*
* See the COPYRIGHT file distributed with this work for additional
* information regarding copyright ownership.
*/
/*! \file
* \brief
* Obtain the list of network interfaces using the getifaddrs(3) library.
*/
#include <ifaddrs.h>
#include <stdbool.h>
#include <isc/strerr.h>
/*% Iterator Magic */
#define IFITER_MAGIC ISC_MAGIC('I', 'F', 'I', 'G')
/*% Valid Iterator */
#define VALID_IFITER(t) ISC_MAGIC_VALID(t, IFITER_MAGIC)
#ifdef __linux
static bool seenv6 = false;
#endif /* ifdef __linux */
/*% Iterator structure */
struct isc_interfaceiter {
unsigned int magic; /*%< Magic number. */
isc_mem_t *mctx;
void *buf; /*%< (unused) */
unsigned int bufsize; /*%< (always 0) */
struct ifaddrs *ifaddrs; /*%< List of ifaddrs */
struct ifaddrs *pos; /*%< Ptr to current ifaddr */
isc_interface_t current; /*%< Current interface data. */
isc_result_t result; /*%< Last result code. */
#ifdef __linux
FILE *proc;
char entry[ISC_IF_INET6_SZ];
isc_result_t valid;
#endif /* ifdef __linux */
};
isc_result_t
isc_interfaceiter_create(isc_mem_t *mctx, isc_interfaceiter_t **iterp) {
isc_interfaceiter_t *iter;
isc_result_t result;
char strbuf[ISC_STRERRORSIZE];
REQUIRE(mctx != NULL);
REQUIRE(iterp != NULL);
REQUIRE(*iterp == NULL);
iter = isc_mem_get(mctx, sizeof(*iter));
iter->mctx = mctx;
iter->buf = NULL;
iter->bufsize = 0;
iter->ifaddrs = NULL;
#ifdef __linux
/*
* Only open "/proc/net/if_inet6" if we have never seen a IPv6
* address returned by getifaddrs().
*/
if (!seenv6) {
iter->proc = fopen("/proc/net/if_inet6", "r");
} else {
iter->proc = NULL;
}
iter->valid = ISC_R_FAILURE;
#endif /* ifdef __linux */
if (getifaddrs(&iter->ifaddrs) < 0) {
strerror_r(errno, strbuf, sizeof(strbuf));
UNEXPECTED_ERROR(__FILE__, __LINE__,
"getting interface addresses: getifaddrs: %s",
strbuf);
result = ISC_R_UNEXPECTED;
goto failure;
}
/*
* A newly created iterator has an undefined position
* until isc_interfaceiter_first() is called.
*/
iter->pos = NULL;
iter->result = ISC_R_FAILURE;
iter->magic = IFITER_MAGIC;
*iterp = iter;
return (ISC_R_SUCCESS);
failure:
#ifdef __linux
if (iter->proc != NULL) {
fclose(iter->proc);
}
#endif /* ifdef __linux */
if (iter->ifaddrs != NULL) { /* just in case */
freeifaddrs(iter->ifaddrs);
}
isc_mem_put(mctx, iter, sizeof(*iter));
return (result);
}
/*
* Get information about the current interface to iter->current.
* If successful, return ISC_R_SUCCESS.
* If the interface has an unsupported address family,
* return ISC_R_IGNORE.
*/
static isc_result_t
internal_current(isc_interfaceiter_t *iter) {
struct ifaddrs *ifa;
int family;
unsigned int namelen;
REQUIRE(VALID_IFITER(iter));
ifa = iter->pos;
#ifdef __linux
if (iter->pos == NULL) {
return (linux_if_inet6_current(iter));
}
#endif /* ifdef __linux */
INSIST(ifa != NULL);
INSIST(ifa->ifa_name != NULL);
if (ifa->ifa_addr == NULL) {
return (ISC_R_IGNORE);
}
family = ifa->ifa_addr->sa_family;
if (family != AF_INET && family != AF_INET6) {
return (ISC_R_IGNORE);
}
#ifdef __linux
if (family == AF_INET6) {
seenv6 = true;
}
#endif /* ifdef __linux */
memset(&iter->current, 0, sizeof(iter->current));
namelen = strlen(ifa->ifa_name);
if (namelen > sizeof(iter->current.name) - 1) {
namelen = sizeof(iter->current.name) - 1;
}
memset(iter->current.name, 0, sizeof(iter->current.name));
memmove(iter->current.name, ifa->ifa_name, namelen);
iter->current.flags = 0;
if ((ifa->ifa_flags & IFF_UP) != 0) {
iter->current.flags |= INTERFACE_F_UP;
}
if ((ifa->ifa_flags & IFF_POINTOPOINT) != 0) {
iter->current.flags |= INTERFACE_F_POINTTOPOINT;
}
if ((ifa->ifa_flags & IFF_LOOPBACK) != 0) {
iter->current.flags |= INTERFACE_F_LOOPBACK;
}
iter->current.af = family;
get_addr(family, &iter->current.address, ifa->ifa_addr, ifa->ifa_name);
if (ifa->ifa_netmask != NULL) {
get_addr(family, &iter->current.netmask, ifa->ifa_netmask,
ifa->ifa_name);
}
if (ifa->ifa_dstaddr != NULL &&
(iter->current.flags & INTERFACE_F_POINTTOPOINT) != 0)
{
get_addr(family, &iter->current.dstaddress, ifa->ifa_dstaddr,
ifa->ifa_name);
}
return (ISC_R_SUCCESS);
}
/*
* Step the iterator to the next interface. Unlike
* isc_interfaceiter_next(), this may leave the iterator
* positioned on an interface that will ultimately
* be ignored. Return ISC_R_NOMORE if there are no more
* interfaces, otherwise ISC_R_SUCCESS.
*/
static isc_result_t
internal_next(isc_interfaceiter_t *iter) {
if (iter->pos != NULL) {
iter->pos = iter->pos->ifa_next;
}
if (iter->pos == NULL) {
#ifdef __linux
if (!seenv6) {
return (linux_if_inet6_next(iter));
}
#endif /* ifdef __linux */
return (ISC_R_NOMORE);
}
return (ISC_R_SUCCESS);
}
static void
internal_destroy(isc_interfaceiter_t *iter) {
#ifdef __linux
if (iter->proc != NULL) {
fclose(iter->proc);
}
iter->proc = NULL;
#endif /* ifdef __linux */
if (iter->ifaddrs) {
freeifaddrs(iter->ifaddrs);
}
iter->ifaddrs = NULL;
}
static void
internal_first(isc_interfaceiter_t *iter) {
#ifdef __linux
linux_if_inet6_first(iter);
#endif /* ifdef __linux */
iter->pos = iter->ifaddrs;
}
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