platform_system_core/libnetutils/ifc_utils.c

671 lines
17 KiB
C

/*
* Copyright 2008, The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <netdb.h>
#include <linux/if.h>
#include <linux/if_ether.h>
#include <linux/if_arp.h>
#include <linux/netlink.h>
#include <linux/route.h>
#include <linux/ipv6_route.h>
#include <linux/rtnetlink.h>
#include <linux/sockios.h>
#include "netutils/ifc.h"
#ifdef ANDROID
#define LOG_TAG "NetUtils"
#include <cutils/log.h>
#include <cutils/properties.h>
#else
#include <stdio.h>
#include <string.h>
#define ALOGD printf
#define ALOGW printf
#endif
#ifdef HAVE_ANDROID_OS
/* SIOCKILLADDR is an Android extension. */
#define SIOCKILLADDR 0x8939
#endif
static int ifc_ctl_sock = -1;
static int ifc_ctl_sock6 = -1;
void printerr(char *fmt, ...);
#define DBG 0
#define INET_ADDRLEN 4
#define INET6_ADDRLEN 16
in_addr_t prefixLengthToIpv4Netmask(int prefix_length)
{
in_addr_t mask = 0;
// C99 (6.5.7): shifts of 32 bits have undefined results
if (prefix_length <= 0 || prefix_length > 32) {
return 0;
}
mask = ~mask << (32 - prefix_length);
mask = htonl(mask);
return mask;
}
int ipv4NetmaskToPrefixLength(in_addr_t mask)
{
int prefixLength = 0;
uint32_t m = (uint32_t)ntohl(mask);
while (m & 0x80000000) {
prefixLength++;
m = m << 1;
}
return prefixLength;
}
static const char *ipaddr_to_string(in_addr_t addr)
{
struct in_addr in_addr;
in_addr.s_addr = addr;
return inet_ntoa(in_addr);
}
int string_to_ip(const char *string, struct sockaddr_storage *ss) {
struct addrinfo hints, *ai;
int ret;
if (ss == NULL) {
return -EFAULT;
}
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_flags = AI_NUMERICHOST;
hints.ai_socktype = SOCK_DGRAM;
ret = getaddrinfo(string, NULL, &hints, &ai);
if (ret == 0) {
memcpy(ss, ai->ai_addr, ai->ai_addrlen);
freeaddrinfo(ai);
}
return ret;
}
int ifc_init(void)
{
int ret;
if (ifc_ctl_sock == -1) {
ifc_ctl_sock = socket(AF_INET, SOCK_DGRAM, 0);
if (ifc_ctl_sock < 0) {
printerr("socket() failed: %s\n", strerror(errno));
}
}
ret = ifc_ctl_sock < 0 ? -1 : 0;
if (DBG) printerr("ifc_init_returning %d", ret);
return ret;
}
int ifc_init6(void)
{
if (ifc_ctl_sock6 == -1) {
ifc_ctl_sock6 = socket(AF_INET6, SOCK_DGRAM, 0);
if (ifc_ctl_sock6 < 0) {
printerr("socket() failed: %s\n", strerror(errno));
}
}
return ifc_ctl_sock6 < 0 ? -1 : 0;
}
void ifc_close(void)
{
if (DBG) printerr("ifc_close");
if (ifc_ctl_sock != -1) {
(void)close(ifc_ctl_sock);
ifc_ctl_sock = -1;
}
}
void ifc_close6(void)
{
if (ifc_ctl_sock6 != -1) {
(void)close(ifc_ctl_sock6);
ifc_ctl_sock6 = -1;
}
}
static void ifc_init_ifr(const char *name, struct ifreq *ifr)
{
memset(ifr, 0, sizeof(struct ifreq));
strncpy(ifr->ifr_name, name, IFNAMSIZ);
ifr->ifr_name[IFNAMSIZ - 1] = 0;
}
int ifc_get_hwaddr(const char *name, void *ptr)
{
int r;
struct ifreq ifr;
ifc_init_ifr(name, &ifr);
r = ioctl(ifc_ctl_sock, SIOCGIFHWADDR, &ifr);
if(r < 0) return -1;
memcpy(ptr, &ifr.ifr_hwaddr.sa_data, ETH_ALEN);
return 0;
}
int ifc_get_ifindex(const char *name, int *if_indexp)
{
int r;
struct ifreq ifr;
ifc_init_ifr(name, &ifr);
r = ioctl(ifc_ctl_sock, SIOCGIFINDEX, &ifr);
if(r < 0) return -1;
*if_indexp = ifr.ifr_ifindex;
return 0;
}
static int ifc_set_flags(const char *name, unsigned set, unsigned clr)
{
struct ifreq ifr;
ifc_init_ifr(name, &ifr);
if(ioctl(ifc_ctl_sock, SIOCGIFFLAGS, &ifr) < 0) return -1;
ifr.ifr_flags = (ifr.ifr_flags & (~clr)) | set;
return ioctl(ifc_ctl_sock, SIOCSIFFLAGS, &ifr);
}
int ifc_up(const char *name)
{
int ret = ifc_set_flags(name, IFF_UP, 0);
if (DBG) printerr("ifc_up(%s) = %d", name, ret);
return ret;
}
int ifc_down(const char *name)
{
int ret = ifc_set_flags(name, 0, IFF_UP);
if (DBG) printerr("ifc_down(%s) = %d", name, ret);
return ret;
}
static void init_sockaddr_in(struct sockaddr *sa, in_addr_t addr)
{
struct sockaddr_in *sin = (struct sockaddr_in *) sa;
sin->sin_family = AF_INET;
sin->sin_port = 0;
sin->sin_addr.s_addr = addr;
}
int ifc_set_addr(const char *name, in_addr_t addr)
{
struct ifreq ifr;
int ret;
ifc_init_ifr(name, &ifr);
init_sockaddr_in(&ifr.ifr_addr, addr);
ret = ioctl(ifc_ctl_sock, SIOCSIFADDR, &ifr);
if (DBG) printerr("ifc_set_addr(%s, xx) = %d", name, ret);
return ret;
}
/*
* Adds or deletes an IP address on an interface.
*
* Action is one of:
* - RTM_NEWADDR (to add a new address)
* - RTM_DELADDR (to delete an existing address)
*
* Returns zero on success and negative errno on failure.
*/
int ifc_act_on_address(int action, const char *name, const char *address,
int prefixlen) {
int ifindex, s, len, ret;
struct sockaddr_storage ss;
void *addr;
size_t addrlen;
struct {
struct nlmsghdr n;
struct ifaddrmsg r;
// Allow for IPv6 address, headers, and padding.
char attrbuf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
NLMSG_ALIGN(sizeof(struct rtattr)) +
NLMSG_ALIGN(INET6_ADDRLEN)];
} req;
struct rtattr *rta;
struct nlmsghdr *nh;
struct nlmsgerr *err;
char buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
NLMSG_ALIGN(sizeof(struct nlmsgerr)) +
NLMSG_ALIGN(sizeof(struct nlmsghdr))];
// Get interface ID.
ifindex = if_nametoindex(name);
if (ifindex == 0) {
return -errno;
}
// Convert string representation to sockaddr_storage.
ret = string_to_ip(address, &ss);
if (ret) {
return ret;
}
// Determine address type and length.
if (ss.ss_family == AF_INET) {
struct sockaddr_in *sin = (struct sockaddr_in *) &ss;
addr = &sin->sin_addr;
addrlen = INET_ADDRLEN;
} else if (ss.ss_family == AF_INET6) {
struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &ss;
addr = &sin6->sin6_addr;
addrlen = INET6_ADDRLEN;
} else {
return -EAFNOSUPPORT;
}
// Fill in netlink structures.
memset(&req, 0, sizeof(req));
// Netlink message header.
req.n.nlmsg_len = NLMSG_LENGTH(sizeof(req.r));
req.n.nlmsg_type = action;
req.n.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
req.n.nlmsg_pid = getpid();
// Interface address message header.
req.r.ifa_family = ss.ss_family;
req.r.ifa_prefixlen = prefixlen;
req.r.ifa_index = ifindex;
// Routing attribute. Contains the actual IP address.
rta = (struct rtattr *) (((char *) &req) + NLMSG_ALIGN(req.n.nlmsg_len));
rta->rta_type = IFA_LOCAL;
rta->rta_len = RTA_LENGTH(addrlen);
req.n.nlmsg_len = NLMSG_ALIGN(req.n.nlmsg_len) + RTA_LENGTH(addrlen);
memcpy(RTA_DATA(rta), addr, addrlen);
s = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (send(s, &req, req.n.nlmsg_len, 0) < 0) {
close(s);
return -errno;
}
len = recv(s, buf, sizeof(buf), 0);
close(s);
if (len < 0) {
return -errno;
}
// Parse the acknowledgement to find the return code.
nh = (struct nlmsghdr *) buf;
if (!NLMSG_OK(nh, (unsigned) len) || nh->nlmsg_type != NLMSG_ERROR) {
return -EINVAL;
}
err = NLMSG_DATA(nh);
// Return code is negative errno.
return err->error;
}
int ifc_add_address(const char *name, const char *address, int prefixlen) {
return ifc_act_on_address(RTM_NEWADDR, name, address, prefixlen);
}
int ifc_del_address(const char *name, const char * address, int prefixlen) {
return ifc_act_on_address(RTM_DELADDR, name, address, prefixlen);
}
/*
* Clears IPv6 addresses on the specified interface.
*/
int ifc_clear_ipv6_addresses(const char *name) {
char rawaddrstr[INET6_ADDRSTRLEN], addrstr[INET6_ADDRSTRLEN];
unsigned int prefixlen;
int lasterror = 0, i, j, ret;
char ifname[64]; // Currently, IFNAMSIZ = 16.
FILE *f = fopen("/proc/net/if_inet6", "r");
if (!f) {
return -errno;
}
// Format:
// 20010db8000a0001fc446aa4b5b347ed 03 40 00 01 wlan0
while (fscanf(f, "%32s %*02x %02x %*02x %*02x %63s\n",
rawaddrstr, &prefixlen, ifname) == 3) {
// Is this the interface we're looking for?
if (strcmp(name, ifname)) {
continue;
}
// Put the colons back into the address.
for (i = 0, j = 0; i < 32; i++, j++) {
addrstr[j] = rawaddrstr[i];
if (i % 4 == 3) {
addrstr[++j] = ':';
}
}
addrstr[j - 1] = '\0';
// Don't delete the link-local address as well, or it will disable IPv6
// on the interface.
if (strncmp(addrstr, "fe80:", 5) == 0) {
continue;
}
ret = ifc_del_address(ifname, addrstr, prefixlen);
if (ret) {
ALOGE("Deleting address %s/%d on %s: %s", addrstr, prefixlen, ifname,
strerror(-ret));
lasterror = ret;
}
}
fclose(f);
return lasterror;
}
/*
* Clears IPv4 addresses on the specified interface.
*/
void ifc_clear_ipv4_addresses(const char *name) {
unsigned count, addr;
ifc_init();
for (count=0, addr=1;((addr != 0) && (count < 255)); count++) {
if (ifc_get_addr(name, &addr) < 0)
break;
if (addr)
ifc_set_addr(name, 0);
}
ifc_close();
}
/*
* Clears all IP addresses on the specified interface.
*/
int ifc_clear_addresses(const char *name) {
ifc_clear_ipv4_addresses(name);
return ifc_clear_ipv6_addresses(name);
}
int ifc_set_hwaddr(const char *name, const void *ptr)
{
int r;
struct ifreq ifr;
ifc_init_ifr(name, &ifr);
ifr.ifr_hwaddr.sa_family = ARPHRD_ETHER;
memcpy(&ifr.ifr_hwaddr.sa_data, ptr, ETH_ALEN);
return ioctl(ifc_ctl_sock, SIOCSIFHWADDR, &ifr);
}
int ifc_set_mask(const char *name, in_addr_t mask)
{
struct ifreq ifr;
int ret;
ifc_init_ifr(name, &ifr);
init_sockaddr_in(&ifr.ifr_addr, mask);
ret = ioctl(ifc_ctl_sock, SIOCSIFNETMASK, &ifr);
if (DBG) printerr("ifc_set_mask(%s, xx) = %d", name, ret);
return ret;
}
int ifc_set_prefixLength(const char *name, int prefixLength)
{
struct ifreq ifr;
// TODO - support ipv6
if (prefixLength > 32 || prefixLength < 0) return -1;
in_addr_t mask = prefixLengthToIpv4Netmask(prefixLength);
ifc_init_ifr(name, &ifr);
init_sockaddr_in(&ifr.ifr_addr, mask);
return ioctl(ifc_ctl_sock, SIOCSIFNETMASK, &ifr);
}
int ifc_get_addr(const char *name, in_addr_t *addr)
{
struct ifreq ifr;
int ret = 0;
ifc_init_ifr(name, &ifr);
if (addr != NULL) {
ret = ioctl(ifc_ctl_sock, SIOCGIFADDR, &ifr);
if (ret < 0) {
*addr = 0;
} else {
*addr = ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr;
}
}
return ret;
}
int ifc_get_info(const char *name, in_addr_t *addr, int *prefixLength, unsigned *flags)
{
struct ifreq ifr;
ifc_init_ifr(name, &ifr);
if (addr != NULL) {
if(ioctl(ifc_ctl_sock, SIOCGIFADDR, &ifr) < 0) {
*addr = 0;
} else {
*addr = ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr;
}
}
if (prefixLength != NULL) {
if(ioctl(ifc_ctl_sock, SIOCGIFNETMASK, &ifr) < 0) {
*prefixLength = 0;
} else {
*prefixLength = ipv4NetmaskToPrefixLength(
((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr);
}
}
if (flags != NULL) {
if(ioctl(ifc_ctl_sock, SIOCGIFFLAGS, &ifr) < 0) {
*flags = 0;
} else {
*flags = ifr.ifr_flags;
}
}
return 0;
}
int ifc_act_on_ipv4_route(int action, const char *ifname, struct in_addr dst, int prefix_length,
struct in_addr gw)
{
struct rtentry rt;
int result;
in_addr_t netmask;
memset(&rt, 0, sizeof(rt));
rt.rt_dst.sa_family = AF_INET;
rt.rt_dev = (void*) ifname;
netmask = prefixLengthToIpv4Netmask(prefix_length);
init_sockaddr_in(&rt.rt_genmask, netmask);
init_sockaddr_in(&rt.rt_dst, dst.s_addr);
rt.rt_flags = RTF_UP;
if (prefix_length == 32) {
rt.rt_flags |= RTF_HOST;
}
if (gw.s_addr != 0) {
rt.rt_flags |= RTF_GATEWAY;
init_sockaddr_in(&rt.rt_gateway, gw.s_addr);
}
ifc_init();
if (ifc_ctl_sock < 0) {
return -errno;
}
result = ioctl(ifc_ctl_sock, action, &rt);
if (result < 0) {
if (errno == EEXIST) {
result = 0;
} else {
result = -errno;
}
}
ifc_close();
return result;
}
/* deprecated - v4 only */
int ifc_create_default_route(const char *name, in_addr_t gw)
{
struct in_addr in_dst, in_gw;
in_dst.s_addr = 0;
in_gw.s_addr = gw;
int ret = ifc_act_on_ipv4_route(SIOCADDRT, name, in_dst, 0, in_gw);
if (DBG) printerr("ifc_create_default_route(%s, %d) = %d", name, gw, ret);
return ret;
}
int ifc_reset_connections(const char *ifname, const int reset_mask)
{
#ifdef HAVE_ANDROID_OS
int result, success;
in_addr_t myaddr;
struct ifreq ifr;
struct in6_ifreq ifr6;
if (reset_mask & RESET_IPV4_ADDRESSES) {
/* IPv4. Clear connections on the IP address. */
ifc_init();
ifc_get_info(ifname, &myaddr, NULL, NULL);
ifc_init_ifr(ifname, &ifr);
init_sockaddr_in(&ifr.ifr_addr, myaddr);
result = ioctl(ifc_ctl_sock, SIOCKILLADDR, &ifr);
ifc_close();
} else {
result = 0;
}
if (reset_mask & RESET_IPV6_ADDRESSES) {
/*
* IPv6. On Linux, when an interface goes down it loses all its IPv6
* addresses, so we don't know which connections belonged to that interface
* So we clear all unused IPv6 connections on the device by specifying an
* empty IPv6 address.
*/
ifc_init6();
// This implicitly specifies an address of ::, i.e., kill all IPv6 sockets.
memset(&ifr6, 0, sizeof(ifr6));
success = ioctl(ifc_ctl_sock6, SIOCKILLADDR, &ifr6);
if (result == 0) {
result = success;
}
ifc_close6();
}
return result;
#else
return 0;
#endif
}
/*
* Removes the default route for the named interface.
*/
int ifc_remove_default_route(const char *ifname)
{
struct rtentry rt;
int result;
ifc_init();
memset(&rt, 0, sizeof(rt));
rt.rt_dev = (void *)ifname;
rt.rt_flags = RTF_UP|RTF_GATEWAY;
init_sockaddr_in(&rt.rt_dst, 0);
if ((result = ioctl(ifc_ctl_sock, SIOCDELRT, &rt)) < 0) {
ALOGD("failed to remove default route for %s: %s", ifname, strerror(errno));
}
ifc_close();
return result;
}
int
ifc_configure(const char *ifname,
in_addr_t address,
uint32_t prefixLength,
in_addr_t gateway,
in_addr_t dns1,
in_addr_t dns2) {
char dns_prop_name[PROPERTY_KEY_MAX];
ifc_init();
if (ifc_up(ifname)) {
printerr("failed to turn on interface %s: %s\n", ifname, strerror(errno));
ifc_close();
return -1;
}
if (ifc_set_addr(ifname, address)) {
printerr("failed to set ipaddr %s: %s\n", ipaddr_to_string(address), strerror(errno));
ifc_close();
return -1;
}
if (ifc_set_prefixLength(ifname, prefixLength)) {
printerr("failed to set prefixLength %d: %s\n", prefixLength, strerror(errno));
ifc_close();
return -1;
}
if (ifc_create_default_route(ifname, gateway)) {
printerr("failed to set default route %s: %s\n", ipaddr_to_string(gateway), strerror(errno));
ifc_close();
return -1;
}
ifc_close();
snprintf(dns_prop_name, sizeof(dns_prop_name), "net.%s.dns1", ifname);
property_set(dns_prop_name, dns1 ? ipaddr_to_string(dns1) : "");
snprintf(dns_prop_name, sizeof(dns_prop_name), "net.%s.dns2", ifname);
property_set(dns_prop_name, dns2 ? ipaddr_to_string(dns2) : "");
return 0;
}