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- /* vim: set expandtab ts=4 sw=4: */
- /*
- * You may redistribute this program and/or modify it under the terms of
- * the GNU General Public License as published by the Free Software Foundation,
- * either version 3 of the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <https://www.gnu.org/licenses/>.
- */
- #include "util/platform/netdev/NetPlatform.h"
- #include "util/platform/Sockaddr.h"
- #include "memory/Allocator.h"
- #include "exception/Except.h"
- #include "wire/Message.h"
- #include "util/AddrTools.h"
- #include "util/Assert.h"
- #include "util/CString.h"
- #include <stdbool.h>
- #include <string.h>
- #include <errno.h>
- #include <stdio.h>
- #include <sys/ioctl.h>
- #include <fcntl.h>
- #include <unistd.h>
- #include <sys/socket.h>
- #include <sys/types.h>
- #include <stdlib.h>
- #include <stddef.h>
- #include <arpa/inet.h>
- #include <linux/if.h>
- #include <linux/route.h>
- #if ! defined(Cjdns_android)
- #include <linux/ipv6_route.h>
- #endif
- #include <linux/netlink.h>
- #include <linux/rtnetlink.h>
- #include <net/if.h>
- // Way to identify our routes as opposed to statically created or otherwise...
- #define RTPROT_CJDNS 52
- /**
- * This hack exists because linux/in.h and linux/in6.h define
- * the same structures, leading to redefinition errors.
- * For the second operand, we're grateful to android/bionic, platform level 21.
- */
- struct Cjdns_in6_ifreq
- {
- struct in6_addr ifr6_addr;
- uint32_t ifr6_prefixlen;
- int ifr6_ifindex;
- };
- /**
- * Get a socket and ifRequest for a given interface by name.
- *
- * @param interfaceName the name of the interface, eg: tun0
- * @param af either AF_INET or AF_INET6
- * @param eg an exception handler in case something goes wrong.
- * this will send a -1 for all errors.
- * @param ifRequestOut an ifreq which will be populated with the interface index of the interface.
- * @return a socket for interacting with this interface.
- */
- static Er_DEFUN(int socketForIfName(const char* interfaceName,
- int af,
- struct Allocator* alloc,
- struct ifreq* ifRequestOut))
- {
- int s;
- if ((s = socket(af, SOCK_DGRAM, 0)) < 0) {
- Er_raise(alloc, "socket() [%s]", strerror(errno));
- }
- memset(ifRequestOut, 0, sizeof(struct ifreq));
- CString_safeStrncpy(ifRequestOut->ifr_name, interfaceName, IFNAMSIZ);
- if (ioctl(s, SIOCGIFINDEX, ifRequestOut) < 0) {
- int err = errno;
- close(s);
- Er_raise(alloc, "ioctl(SIOCGIFINDEX) [%s]", strerror(err));
- }
- Er_ret(s);
- }
- /** don't use if_nametoindex() because it accesses the filesystem. */
- static Er_DEFUN(int ifIndexForName(const char* interfaceName, struct Allocator* alloc))
- {
- struct ifreq ifRequest;
- int s = Er(socketForIfName(interfaceName, AF_INET, alloc, &ifRequest));
- close(s);
- Er_ret(ifRequest.ifr_ifindex);
- }
- static Er_DEFUN(void checkInterfaceUp(int socket,
- struct ifreq* ifRequest,
- struct Log* logger,
- struct Allocator* alloc))
- {
- if (ioctl(socket, SIOCGIFFLAGS, ifRequest) < 0) {
- int err = errno;
- close(socket);
- Er_raise(alloc, "ioctl(SIOCGIFFLAGS) [%s]", strerror(err));
- }
- if (ifRequest->ifr_flags & IFF_UP & IFF_RUNNING) {
- // already up.
- Er_ret();
- }
- Log_info(logger, "Bringing up interface [%s]", ifRequest->ifr_name);
- ifRequest->ifr_flags |= IFF_UP | IFF_RUNNING;
- if (ioctl(socket, SIOCSIFFLAGS, ifRequest) < 0) {
- int err = errno;
- close(socket);
- Er_raise(alloc, "ioctl(SIOCSIFFLAGS) [%s]", strerror(err));
- }
- Er_ret();
- }
- Er_DEFUN(void NetPlatform_addAddress(const char* interfaceName,
- const uint8_t* address,
- int prefixLen,
- int addrFam,
- struct Log* logger,
- struct Allocator* tempAlloc))
- {
- struct ifreq ifRequest;
- int s = Er(socketForIfName(interfaceName, addrFam, tempAlloc, &ifRequest));
- int ifIndex = ifRequest.ifr_ifindex;
- // checkInterfaceUp() clobbers the ifindex.
- Er(checkInterfaceUp(s, &ifRequest, logger, tempAlloc));
- if (addrFam == AF_INET6) {
- struct Cjdns_in6_ifreq ifr6 = {
- .ifr6_ifindex = ifIndex,
- .ifr6_prefixlen = prefixLen
- };
- memcpy(&ifr6.ifr6_addr, address, 16);
- if (ioctl(s, SIOCSIFADDR, &ifr6) < 0) {
- int err = errno;
- close(s);
- if (err == EPERM) {
- Er_raise(tempAlloc, "ioctl permission denied, Are you root and is ipv6 enabled?");
- } else {
- Er_raise(tempAlloc, "ioctl(SIOCSIFADDR) failed: [%s]", strerror(err));
- }
- }
- } else if (addrFam == AF_INET) {
- struct sockaddr_in sin = { .sin_family = AF_INET, .sin_port = 0 };
- memcpy(&sin.sin_addr.s_addr, address, 4);
- memcpy(&ifRequest.ifr_addr, &sin, sizeof(struct sockaddr));
- if (ioctl(s, SIOCSIFADDR, &ifRequest) < 0) {
- int err = errno;
- close(s);
- Er_raise(tempAlloc, "ioctl(SIOCSIFADDR) failed: [%s]", strerror(err));
- }
- uint32_t x = (uint32_t)~0 << (32 - prefixLen);
- x = Endian_hostToBigEndian32(x);
- memcpy(&sin.sin_addr, &x, 4);
- memcpy(&ifRequest.ifr_addr, &sin, sizeof(struct sockaddr_in));
- if (ioctl(s, SIOCSIFNETMASK, &ifRequest) < 0) {
- int err = errno;
- close(s);
- Er_raise(tempAlloc, "ioctl(SIOCSIFNETMASK) failed: [%s]", strerror(err));
- }
- } else {
- Assert_true(0);
- }
- close(s);
- Er_ret();
- }
- Er_DEFUN(void NetPlatform_setMTU(const char* interfaceName,
- uint32_t mtu,
- struct Log* logger,
- struct Allocator* alloc))
- {
- struct ifreq ifRequest;
- int s = Er(socketForIfName(interfaceName, AF_INET6, alloc, &ifRequest));
- Log_info(logger, "Setting MTU for device [%s] to [%u] bytes.", interfaceName, mtu);
- ifRequest.ifr_mtu = mtu;
- if (ioctl(s, SIOCSIFMTU, &ifRequest) < 0) {
- int err = errno;
- close(s);
- Er_raise(alloc, "ioctl(SIOCSIFMTU) [%s]", strerror(err));
- }
- close(s);
- Er_ret();
- }
- struct IfIndexAttr {
- struct rtattr rta;
- int ifIndex;
- };
- Assert_compileTime(sizeof(struct IfIndexAttr) == 8);
- struct RouteRequest {
- struct nlmsghdr hdr;
- struct rtmsg route;
- };
- Assert_compileTime(sizeof(struct nlmsghdr) == 16);
- Assert_compileTime(sizeof(struct rtmsg) == 12);
- Assert_compileTime(sizeof(struct RouteRequest) == 28);
- struct RouteInfo;
- struct RouteInfo {
- struct RouteInfo* next;
- int protocol;
- int prefix;
- uint8_t dstAddr[16];
- int ifIndex;
- int af;
- };
- #define BUFF_SZ 16384
- static Er_DEFUN(bool getMoreMessages(struct RouteInfo** rio,
- int sock,
- int ifIndex,
- struct Allocator* alloc))
- {
- bool retVal = false;
- struct Allocator* tempAlloc = Allocator_child(alloc);
- struct Message* msg = Message_new(BUFF_SZ, 0, tempAlloc);
- ssize_t sz = recv(sock, msg->msgbytes, BUFF_SZ, MSG_TRUNC);
- if (sz < (ssize_t)sizeof(struct nlmsghdr)) {
- Er_raise(tempAlloc, "recv() -> %s", strerror(errno));
- } else if (sz > BUFF_SZ) {
- Er_raise(tempAlloc, "recv() -> buffer too small");
- }
- Er_assert(Message_truncate(msg, sz));
- //printf("%s\n", Hex_print(msg->bytes, Message_getLength(msg), tempAlloc));
- while (Message_getLength(msg)) {
- struct RouteInfo ri = { .protocol = 0 };
- int initMsgLen = Message_getLength(msg);
- struct nlmsghdr hdr;
- Er(Message_epop(msg, &hdr, sizeof(struct nlmsghdr)));
- //printf("\nHEADER %04x %04x\n", hdr.nlmsg_type, hdr.nlmsg_flags);
- if (hdr.nlmsg_flags & NLM_F_MULTI) { retVal = true; }
- if (hdr.nlmsg_type == NLMSG_DONE) {
- Allocator_free(tempAlloc);
- Er_ret(false);
- }
- struct rtmsg rtm;
- Er(Message_epop(msg, &rtm, sizeof(struct rtmsg)));
- ri.prefix = rtm.rtm_dst_len;
- ri.af = rtm.rtm_family;
- ri.protocol = rtm.rtm_protocol;
- for (;;) {
- int remainingLen = hdr.nlmsg_len - (initMsgLen - Message_getLength(msg));
- if (remainingLen <= (int)sizeof(struct rtattr)) { break; }
- struct rtattr attrHead;
- //printf(">%s %d\n", Hex_print(msg->bytes, Message_getLength(msg), tempAlloc), remainingLen);
- Er(Message_epop(msg, &attrHead, sizeof(struct rtattr)));
- switch (attrHead.rta_type) {
- case RTA_OIF: {
- if (attrHead.rta_len != 8) {
- Er_raise(alloc, "unexpected rta_len for ifIndex");
- }
- Er(Message_epop(msg, &ri.ifIndex, 4));
- break;
- }
- case RTA_DST: {
- if (rtm.rtm_family == AF_INET6) {
- if (attrHead.rta_len != 20) {
- Er_raise(alloc, "unexpected rta_len for RTA_DST (ipv6)");
- }
- Er(Message_epop(msg, ri.dstAddr, 16));
- } else if (rtm.rtm_family == AF_INET) {
- if (attrHead.rta_len != 8) {
- Er_raise(alloc, "unexpected rta_len for RTA_DST (ipv4)");
- }
- Er(Message_epop(msg, ri.dstAddr, 4));
- } else {
- Er_raise(alloc, "unexpected af %d", rtm.rtm_family);
- }
- break;
- }
- default: {
- int effectiveLen = RTA_ALIGN(attrHead.rta_len);
- //printf("unrecognized %d (length %d)\n", attrHead.rta_type, effectiveLen);
- Er(Message_epop(msg, NULL, effectiveLen - sizeof(struct rtattr)));
- break;
- }
- }
- }
- if (rtm.rtm_table != RT_TABLE_MAIN) { continue; }
- if (rtm.rtm_type != RTN_UNICAST) { continue; }
- if (ri.ifIndex != ifIndex) { continue; }
- if (ri.protocol != RTPROT_CJDNS) { continue; }
- struct RouteInfo* outRi = Allocator_clone(alloc, &ri);
- outRi->next = *rio;
- *rio = outRi;
- }
- Allocator_free(tempAlloc);
- Er_ret(retVal);
- }
- static Er_DEFUN(struct RouteInfo* getRoutes(int sock,
- int ifIndex,
- struct Allocator* alloc))
- {
- struct RouteRequest req = {
- .hdr = {
- .nlmsg_len = sizeof(struct RouteRequest),
- .nlmsg_type = RTM_GETROUTE,
- .nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT | NLM_F_MULTI
- },
- .route = {
- .rtm_family = AF_UNSPEC
- }
- };
- ssize_t sz = send(sock, &req, req.hdr.nlmsg_len, 0);
- if (sz < 0) {
- Er_raise(alloc, "send() -> %s", strerror(errno));
- }
- struct RouteInfo* ri = NULL;
- while (Er(getMoreMessages(&ri, sock, ifIndex, alloc))) ;
- Er_ret(ri);
- }
- static void bitShave(uint8_t* address, int prefix, int af)
- {
- int top;
- if (af == AF_INET) {
- top = 4;
- } else if (af == AF_INET6) {
- top = 16;
- } else {
- Assert_failure("bad af");
- }
- if (prefix < (8 * top)) {
- address[prefix >> 3] &= ( 0xff << (8 - (prefix % 8)) );
- for (int i = (prefix >> 3) + 1; i < top; i++) {
- address[i] = 0;
- }
- }
- }
- static Er_DEFUN(void addDeleteRoutes(int sock,
- bool delete,
- struct RouteInfo* ri,
- struct Allocator* tempAlloc))
- {
- struct Message* msg = Message_new(0, 512, tempAlloc);
- for (;ri;ri = ri->next) {
- struct IfIndexAttr ifa = {
- .rta = {
- .rta_len = sizeof(struct IfIndexAttr),
- .rta_type = RTA_OIF
- },
- .ifIndex = ri->ifIndex
- };
- Er(Message_epush(msg, &ifa, sizeof(struct IfIndexAttr)));
- int addrLen = (ri->af == AF_INET6) ? 16 : 4;
- Er(Message_epush(msg, ri->dstAddr, addrLen));
- bitShave(msg->msgbytes, ri->prefix, ri->af);
- struct rtattr rta = { .rta_len = sizeof(struct rtattr) + addrLen, .rta_type = RTA_DST };
- Er(Message_epush(msg, &rta, sizeof(struct rtattr)));
- struct rtmsg route = {
- .rtm_family = ri->af,
- .rtm_dst_len = ri->prefix,
- .rtm_table = RT_TABLE_MAIN,
- .rtm_scope = (delete) ? RT_SCOPE_NOWHERE : RT_SCOPE_LINK,
- .rtm_protocol = (delete) ? RTPROT_UNSPEC : ri->protocol,
- .rtm_type = (delete) ? RTN_UNSPEC : RTN_UNICAST
- };
- Er(Message_epush(msg, &route, sizeof(struct rtmsg)));
- struct nlmsghdr hdr = {
- .nlmsg_len = Message_getLength(msg) + sizeof(struct nlmsghdr),
- .nlmsg_type = (delete) ? RTM_DELROUTE : RTM_NEWROUTE,
- .nlmsg_flags = NLM_F_REQUEST | ((delete) ? 0 : NLM_F_CREATE) // | NLM_F_ACK,
- };
- Er(Message_epush(msg, &hdr, sizeof(struct nlmsghdr)));
- ssize_t sz = send(sock, msg->msgbytes, Message_getLength(msg), 0);
- if (sz < 0) {
- Er_raise(tempAlloc, "send() -> %s", strerror(errno));
- }
- Message_reset(msg);
- }
- Er_ret();
- }
- static int closeSocket(struct Allocator_OnFreeJob* job)
- {
- long sock = (long) job->userData;
- close((int)sock);
- return 0;
- }
- static Er_DEFUN(int mkSocket(struct Allocator* alloc))
- {
- int sock = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
- if (sock < 0) {
- Er_raise(alloc, "socket(PF_NETLINK) -> %s", strerror(errno));
- }
- Allocator_onFree(alloc, closeSocket, (void*) ((long) sock));
- Er_ret(sock);
- }
- static struct RouteInfo* riForSockaddrs(struct Sockaddr** prefixSet,
- int prefixCount,
- int ifIndex,
- struct Allocator* alloc)
- {
- struct RouteInfo* out = NULL;
- for (int i = 0; i < prefixCount; i++) {
- struct RouteInfo* ri = Allocator_calloc(alloc, sizeof(struct RouteInfo), 1);
- ri->protocol = RTPROT_CJDNS;
- ri->prefix = Sockaddr_getPrefix(prefixSet[i]);
- ri->af = Sockaddr_getFamily(prefixSet[i]);
- ri->ifIndex = ifIndex;
- uint8_t* addr;
- int len = Sockaddr_getAddress(prefixSet[i], &addr);
- Assert_true(len == 4 || len == 16);
- Bits_memcpy(ri->dstAddr, addr, len);
- ri->next = out;
- out = ri;
- }
- return out;
- }
- static void logRis(struct RouteInfo* ri, struct Log* logger, char* msg)
- {
- for (; ri; ri = ri->next) {
- uint8_t addrBuff[40] = {0};
- if (ri->af == AF_INET6) {
- AddrTools_printIp(addrBuff, ri->dstAddr);
- } else if (ri->af == AF_INET) {
- snprintf(addrBuff, 40, "%u.%u.%u.%u",
- ri->dstAddr[0], ri->dstAddr[1], ri->dstAddr[2], ri->dstAddr[3]);
- }
- Log_debug(logger, "%s %s/%u", msg, addrBuff, ri->prefix);
- }
- }
- Er_DEFUN(void NetPlatform_setRoutes(const char* ifName,
- struct Sockaddr** prefixSet,
- int prefixCount,
- struct Log* logger,
- struct Allocator* tempAlloc))
- {
- int ifIndex = Er(ifIndexForName(ifName, tempAlloc));
- struct RouteInfo* newRi = riForSockaddrs(prefixSet, prefixCount, ifIndex, tempAlloc);
- int sock = Er(mkSocket(tempAlloc));
- struct RouteInfo* oldRi = Er(getRoutes(sock, ifIndex, tempAlloc));
- logRis(oldRi, logger, "DELETE ROUTE");
- Er(addDeleteRoutes(sock, true, oldRi, tempAlloc));
- logRis(newRi, logger, "ADD ROUTE");
- Er(addDeleteRoutes(sock, false, newRi, tempAlloc));
- Er_ret();
- }
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