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-rw-r--r--src/contrib/net.c747
1 files changed, 747 insertions, 0 deletions
diff --git a/src/contrib/net.c b/src/contrib/net.c
new file mode 100644
index 0000000..3de4a71
--- /dev/null
+++ b/src/contrib/net.c
@@ -0,0 +1,747 @@
+/* Copyright (C) 2023 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+ This program is free software: you can redistribute it 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 <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/types.h> // OpenBSD
+#include <netinet/tcp.h> // TCP_FASTOPEN
+#include <netinet/in.h>
+#include <poll.h>
+#include <stdbool.h>
+#include <sys/socket.h>
+#include <sys/uio.h>
+#include <unistd.h>
+
+#include "libknot/errcode.h"
+#include "contrib/macros.h"
+#include "contrib/net.h"
+#include "contrib/sockaddr.h"
+#include "contrib/time.h"
+
+/*!
+ * \brief Enable socket option.
+ */
+static int sockopt_enable(int sock, int level, int optname)
+{
+ const int enable = 1;
+ if (setsockopt(sock, level, optname, &enable, sizeof(enable)) != 0) {
+ return knot_map_errno();
+ }
+
+ return KNOT_EOK;
+}
+
+/*!
+ * \brief Create a non-blocking socket.
+ *
+ * Prefer SOCK_NONBLOCK if available to save one fcntl() syscall.
+ *
+ */
+static int socket_create(int family, int type, int proto)
+{
+#ifdef SOCK_NONBLOCK
+ type |= SOCK_NONBLOCK;
+#endif
+ int sock = socket(family, type, proto);
+ if (sock < 0) {
+ return knot_map_errno();
+ }
+
+#ifndef SOCK_NONBLOCK
+ if (fcntl(sock, F_SETFL, O_NONBLOCK) != 0) {
+ int ret = knot_map_errno();
+ close(sock);
+ return ret;
+ }
+#endif
+
+/*
+ * OS X doesn't support MSG_NOSIGNAL. Use SO_NOSIGPIPE socket option instead.
+ */
+#if defined(__APPLE__) && !defined(MSG_NOSIGNAL)
+#define MSG_NOSIGNAL 0
+ int ret = sockopt_enable(sock, SOL_SOCKET, SO_NOSIGPIPE);
+ if (ret != KNOT_EOK) {
+ return ret;
+ }
+#endif
+
+ return sock;
+}
+
+int net_unbound_socket(int type, const struct sockaddr_storage *addr)
+{
+ if (addr == NULL) {
+ return KNOT_EINVAL;
+ }
+
+ /* Create socket. */
+ return socket_create(addr->ss_family, type, 0);
+}
+
+struct option {
+ int level;
+ int name;
+};
+
+/*!
+ * \brief Get setsock option for binding non-local address.
+ */
+static const struct option *nonlocal_option(int family)
+{
+ static const struct option ipv4 = {
+ #if defined(IP_FREEBIND)
+ IPPROTO_IP, IP_FREEBIND
+ #elif defined(IP_BINDANY)
+ IPPROTO_IP, IP_BINDANY
+ #else
+ 0, 0
+ #endif
+ };
+
+ static const struct option ipv6 = {
+ #if defined(IP_FREEBIND)
+ IPPROTO_IP, IP_FREEBIND
+ #elif defined(IPV6_BINDANY)
+ IPPROTO_IPV6, IPV6_BINDANY
+ #else
+ 0, 0
+ #endif
+
+ };
+
+ switch (family) {
+ case AF_INET: return &ipv4;
+ case AF_INET6: return &ipv6;
+ default:
+ return NULL;
+ }
+}
+
+static int enable_nonlocal(int sock, int family)
+{
+ const struct option *opt = nonlocal_option(family);
+ if (opt == NULL || opt->name == 0) {
+ return KNOT_ENOTSUP;
+ }
+
+ return sockopt_enable(sock, opt->level, opt->name);
+}
+
+static int enable_reuseport(int sock)
+{
+#ifdef ENABLE_REUSEPORT
+# if defined(__FreeBSD__)
+ return sockopt_enable(sock, SOL_SOCKET, SO_REUSEPORT_LB);
+# else
+ return sockopt_enable(sock, SOL_SOCKET, SO_REUSEPORT);
+# endif
+#else
+ return KNOT_ENOTSUP;
+#endif
+}
+
+static void unlink_unix_socket(const struct sockaddr_storage *addr)
+{
+ char path[SOCKADDR_STRLEN] = { 0 };
+ sockaddr_tostr(path, sizeof(path), addr);
+ unlink(path);
+}
+
+int net_bound_socket(int type, const struct sockaddr_storage *addr,
+ net_bind_flag_t flags, mode_t unix_mode)
+{
+ /* Create socket. */
+ int sock = net_unbound_socket(type, addr);
+ if (sock < 0) {
+ return sock;
+ }
+
+ /* Unlink UNIX sock if exists. */
+ if (addr->ss_family == AF_UNIX) {
+ unlink_unix_socket(addr);
+ }
+
+ /* Reuse old address if taken. */
+ int ret = sockopt_enable(sock, SOL_SOCKET, SO_REUSEADDR);
+ if (ret != KNOT_EOK) {
+ close(sock);
+ return ret;
+ }
+
+#if defined(__linux__)
+ /* Set MSS (Maximum Segment Size) limit. */
+ if (addr->ss_family != AF_UNIX && type == SOCK_STREAM) {
+ const int mss = KNOT_TCP_MSS;
+ if (setsockopt(sock, IPPROTO_TCP, TCP_MAXSEG, &mss, sizeof(mss)) != 0) {
+ ret = knot_map_errno();
+ close(sock);
+ return ret;
+ }
+ }
+#endif
+
+ /* Don't bind IPv4 for IPv6 any address. */
+ if (addr->ss_family == AF_INET6) {
+ ret = sockopt_enable(sock, IPPROTO_IPV6, IPV6_V6ONLY);
+ if (ret != KNOT_EOK) {
+ close(sock);
+ return ret;
+ }
+ }
+
+ /* Allow bind to non-local address. */
+ if (flags & NET_BIND_NONLOCAL) {
+ ret = enable_nonlocal(sock, addr->ss_family);
+ if (ret != KNOT_EOK) {
+ close(sock);
+ return ret;
+ }
+ }
+
+ /* Allow to bind the same address by multiple threads. */
+ if (flags & NET_BIND_MULTIPLE) {
+ ret = enable_reuseport(sock);
+ if (ret != KNOT_EOK) {
+ close(sock);
+ return ret;
+ }
+ }
+
+ /* Bind to specified address. */
+ ret = bind(sock, (const struct sockaddr *)addr, sockaddr_len(addr));
+ if (ret < 0) {
+ ret = knot_map_errno();
+ close(sock);
+ return ret;
+ }
+
+ if (addr->ss_family == AF_UNIX && unix_mode != 0) {
+ const char *path = ((const struct sockaddr_un *)addr)->sun_path;
+ if (chmod(path, unix_mode) != 0) {
+ ret = knot_map_errno();
+ close(sock);
+ return ret;
+ }
+ }
+
+ return sock;
+}
+
+static int tfo_connect(int sock, const struct sockaddr_storage *addr)
+{
+#if defined(__linux__)
+ /* connect() will be called implicitly with sendmsg(). */
+ return KNOT_EOK;
+#elif defined(__FreeBSD__)
+ return sockopt_enable(sock, IPPROTO_TCP, TCP_FASTOPEN);
+#elif defined(__APPLE__)
+ /* Connection is performed lazily when first data is sent. */
+ sa_endpoints_t ep = {
+ .sae_dstaddr = (const struct sockaddr *)addr,
+ .sae_dstaddrlen = sockaddr_len(addr)
+ };
+ int flags = CONNECT_DATA_IDEMPOTENT | CONNECT_RESUME_ON_READ_WRITE;
+
+ int ret = connectx(sock, &ep, SAE_ASSOCID_ANY, flags, NULL, 0, NULL, NULL);
+ return (ret == 0 ? KNOT_EOK : knot_map_errno());
+#else
+ return KNOT_ENOTSUP;
+#endif
+}
+
+int net_connected_socket(int type, const struct sockaddr_storage *dst_addr,
+ const struct sockaddr_storage *src_addr, bool tfo)
+{
+ if (dst_addr == NULL) {
+ return KNOT_EINVAL;
+ }
+
+ /* Check port. */
+ if (sockaddr_port(dst_addr) == 0) {
+ return KNOT_NET_EADDR;
+ }
+
+ /* Bind to specific source address - if set. */
+ int sock = -1;
+ if (src_addr && src_addr->ss_family != AF_UNSPEC) {
+ sock = net_bound_socket(type, src_addr, 0, 0);
+ } else {
+ sock = net_unbound_socket(type, dst_addr);
+ }
+ if (sock < 0) {
+ return sock;
+ }
+
+ /* Connect to destination. */
+ if (tfo && net_is_stream(sock)) {
+ int ret = tfo_connect(sock, dst_addr);
+ if (ret != KNOT_EOK) {
+ close(sock);
+ return ret;
+ }
+ } else {
+ int ret = connect(sock, (const struct sockaddr *)dst_addr,
+ sockaddr_len(dst_addr));
+ if (ret != 0 && errno != EINPROGRESS) {
+ ret = knot_map_errno();
+ close(sock);
+ return ret;
+ }
+ }
+
+ return sock;
+}
+
+int net_bound_tfo(int sock, int backlog)
+{
+#if defined(TCP_FASTOPEN)
+#if defined(__APPLE__)
+ if (backlog > 0) {
+ backlog = 1; // just on-off switch on macOS
+ }
+#endif
+ if (setsockopt(sock, IPPROTO_TCP, TCP_FASTOPEN, &backlog, sizeof(backlog)) != 0) {
+ return knot_map_errno();
+ }
+
+ return KNOT_EOK;
+#endif
+ return KNOT_ENOTSUP;
+}
+
+bool net_is_connected(int sock)
+{
+ struct sockaddr_storage addr;
+ socklen_t len = sizeof(addr);
+ return (getpeername(sock, (struct sockaddr *)&addr, &len) == 0);
+}
+
+int net_socktype(int sock)
+{
+ int type;
+ socklen_t size = sizeof(type);
+
+ if (getsockopt(sock, SOL_SOCKET, SO_TYPE, &type, &size) == 0) {
+ return type;
+ } else {
+ return AF_UNSPEC;
+ }
+}
+
+bool net_is_stream(int sock)
+{
+ return net_socktype(sock) == SOCK_STREAM;
+}
+
+int net_accept(int sock, struct sockaddr_storage *addr)
+{
+ socklen_t len = sizeof(*addr);
+ socklen_t *addr_len = (addr != NULL) ? &len : NULL;
+
+ int remote = -1;
+
+#if defined(HAVE_ACCEPT4) && defined(SOCK_NONBLOCK)
+ remote = accept4(sock, (struct sockaddr *)addr, addr_len, SOCK_NONBLOCK);
+ if (remote < 0) {
+ return knot_map_errno();
+ }
+#else
+ remote = accept(sock, (struct sockaddr *)addr, addr_len);
+ if (fcntl(remote, F_SETFL, O_NONBLOCK) != 0) {
+ int error = knot_map_errno();
+ close(remote);
+ return error;
+ }
+#endif
+
+ return remote;
+}
+
+void net_reset(int sock)
+{
+ struct sockaddr unspec = { .sa_family = AF_UNSPEC };
+ (void)connect(sock, &unspec, sizeof(unspec));
+}
+
+/* -- I/O interface handling partial -------------------------------------- */
+
+/*!
+ * \brief Perform \a poll() on one socket.
+ */
+static int poll_one(int fd, int events, int timeout_ms)
+{
+ struct pollfd pfd = {
+ .fd = fd,
+ .events = events
+ };
+
+ return poll(&pfd, 1, timeout_ms);
+}
+
+/*!
+ * \brief Check if we should wait for I/O readiness.
+ *
+ * \param error \a errno set by the failed I/O operation.
+ */
+static bool io_should_wait(int error)
+{
+ if (error == EAGAIN || error == EWOULDBLOCK || /* Socket data not ready. */
+ error == ENOMEM || error == ENOBUFS) { /* Insufficient resources. */
+ return true;
+ }
+
+#ifndef __linux__
+ /* FreeBSD: connection in progress. */
+ if (error == ENOTCONN) {
+ return true;
+ }
+#endif
+
+ return false;
+}
+
+/*!
+ * \brief Check if we should wait again.
+ *
+ * \param error \a errno set by the failed wait operation.
+ */
+static bool wait_should_retry(int error)
+{
+ if (error == EINTR || /* System call interrupted. */
+ error == EAGAIN || error == ENOMEM) { /* Insufficient resources. */
+ return true;
+ }
+ return false;
+}
+
+/*!
+ * \brief I/O operation callbacks.
+ */
+struct io {
+ ssize_t (*process)(int sockfd, struct msghdr *msg, int timeout_ms);
+ int (*wait)(int sockfd, int timeout_ms);
+};
+
+/*!
+ * \brief Get total size of I/O vector in a message.
+ */
+static size_t msg_iov_len(const struct msghdr *msg)
+{
+ size_t total = 0;
+
+ for (int i = 0; i < msg->msg_iovlen; i++) {
+ total += msg->msg_iov[i].iov_len;
+ }
+
+ return total;
+}
+
+/*!
+ * \brief Shift processed data out of message IO vectors.
+ */
+static void msg_iov_shift(struct msghdr *msg, size_t done)
+{
+ struct iovec *iov = msg->msg_iov;
+ int iovlen = msg->msg_iovlen;
+
+ for (int i = 0; i < iovlen && done > 0; i++) {
+ if (iov[i].iov_len > done) {
+ iov[i].iov_base += done;
+ iov[i].iov_len -= done;
+ done = 0;
+ } else {
+ done -= iov[i].iov_len;
+ msg->msg_iov += 1;
+ msg->msg_iovlen -= 1;
+ }
+ }
+
+ assert(done == 0);
+}
+
+#define TIMEOUT_CTX_INIT \
+ struct timespec begin, end; \
+ if (*timeout_ptr > 0) { \
+ clock_gettime(CLOCK_MONOTONIC, &begin); \
+ }
+
+#define TIMEOUT_CTX_UPDATE \
+ if (*timeout_ptr > 0) { \
+ clock_gettime(CLOCK_MONOTONIC, &end); \
+ int running_ms = time_diff_ms(&begin, &end); \
+ *timeout_ptr = MAX(*timeout_ptr - running_ms, 0); \
+ }
+
+/*!
+ * \brief Perform an I/O operation with a socket with waiting.
+ *
+ * \param oneshot If set, doesn't wait until the buffer is fully processed.
+ */
+static ssize_t io_exec(const struct io *io, int fd, struct msghdr *msg,
+ bool oneshot, int *timeout_ptr)
+{
+ size_t done = 0;
+ size_t total = msg_iov_len(msg);
+
+ for (;;) {
+ /* Perform I/O. */
+ ssize_t ret = io->process(fd, msg, *timeout_ptr);
+ if (ret == -1 && errno == EINTR) {
+ continue;
+ }
+ if (ret > 0) {
+ done += ret;
+ if (oneshot || done == total) {
+ break;
+ }
+ msg_iov_shift(msg, ret);
+ }
+
+ /* Wait for data readiness. */
+ if (ret > 0 || (ret == -1 && io_should_wait(errno))) {
+ for (;;) {
+ TIMEOUT_CTX_INIT
+
+ ret = io->wait(fd, *timeout_ptr);
+
+ if (ret == 1) {
+ TIMEOUT_CTX_UPDATE
+ /* Ready, retry process. */
+ break;
+ } else if (ret == -1 && wait_should_retry(errno)) {
+ TIMEOUT_CTX_UPDATE
+ /* Interrupted or transient error, continue waiting. */
+ continue;
+ } else if (ret == 0) {
+ /* Timed out, exit. */
+ return KNOT_ETIMEOUT;
+ } else {
+ /* In specific circumstances with Valgrind,
+ * poll() returns wrong value.
+ */
+ assert(ret <= 1);
+ assert(ret >= -1);
+ /* Other error, exit. */
+ return KNOT_ECONN;
+ }
+ }
+ } else {
+ /* Disconnect or error. */
+ return KNOT_ECONN;
+ }
+ }
+
+ return done;
+}
+
+static ssize_t recv_process(int fd, struct msghdr *msg, int timeout_ms)
+{
+ return recvmsg(fd, msg, MSG_DONTWAIT | MSG_NOSIGNAL);
+}
+
+static int recv_wait(int fd, int timeout_ms)
+{
+ return poll_one(fd, POLLIN, timeout_ms);
+}
+
+static ssize_t recv_data(int sock, struct msghdr *msg, bool oneshot, int *timeout_ptr)
+{
+ static const struct io RECV_IO = {
+ .process = recv_process,
+ .wait = recv_wait
+ };
+
+ return io_exec(&RECV_IO, sock, msg, oneshot, timeout_ptr);
+}
+
+static ssize_t send_process_tfo(int fd, struct msghdr *msg, int timeout_ms)
+{
+#if defined(__linux__)
+ int ret = sendmsg(fd, msg, MSG_FASTOPEN);
+ if (ret != 0 && errno == EINPROGRESS) {
+ if (poll_one(fd, POLLOUT, timeout_ms) != 1) {
+ errno = ETIMEDOUT;
+ return -1;
+ }
+ ret = sendmsg(fd, msg, MSG_NOSIGNAL);
+ }
+ return ret;
+#else
+ return sendmsg(fd, msg, MSG_NOSIGNAL);
+#endif
+}
+
+static ssize_t send_process(int fd, struct msghdr *msg, int timeout_ms)
+{
+ return sendmsg(fd, msg, MSG_NOSIGNAL);
+}
+
+static int send_wait(int fd, int timeout_ms)
+{
+ return poll_one(fd, POLLOUT, timeout_ms);
+}
+
+static ssize_t send_data(int sock, struct msghdr *msg, int *timeout_ptr, bool tfo)
+{
+ static const struct io SEND_IO = {
+ .process = send_process,
+ .wait = send_wait
+ };
+ static const struct io SEND_IO_TFO = {
+ .process = send_process_tfo,
+ .wait = send_wait
+ };
+
+ return io_exec(tfo ? &SEND_IO_TFO : &SEND_IO, sock, msg, false, timeout_ptr);
+}
+
+/* -- generic stream and datagram I/O -------------------------------------- */
+
+ssize_t net_base_send(int sock, const uint8_t *buffer, size_t size,
+ const struct sockaddr_storage *addr, int timeout_ms)
+{
+ if (sock < 0 || buffer == NULL) {
+ return KNOT_EINVAL;
+ }
+
+ struct iovec iov = { 0 };
+ iov.iov_base = (void *)buffer;
+ iov.iov_len = size;
+
+ struct msghdr msg = { 0 };
+ msg.msg_name = (void *)addr;
+ msg.msg_namelen = sockaddr_len(addr);
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+
+ int ret = send_data(sock, &msg, &timeout_ms, false);
+ if (ret < 0) {
+ return ret;
+ } else if (ret != size) {
+ return KNOT_ECONN;
+ }
+
+ return ret;
+}
+
+ssize_t net_base_recv(int sock, uint8_t *buffer, size_t size,
+ struct sockaddr_storage *addr, int timeout_ms)
+{
+ if (sock < 0 || buffer == NULL) {
+ return KNOT_EINVAL;
+ }
+
+ struct iovec iov = { 0 };
+ iov.iov_base = buffer;
+ iov.iov_len = size;
+
+ struct msghdr msg = { 0 };
+ msg.msg_name = (void *)addr;
+ msg.msg_namelen = addr ? sizeof(*addr) : 0;
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+
+ return recv_data(sock, &msg, true, &timeout_ms);
+}
+
+ssize_t net_dgram_send(int sock, const uint8_t *buffer, size_t size,
+ const struct sockaddr_storage *addr)
+{
+ return net_base_send(sock, buffer, size, addr, 0);
+}
+
+ssize_t net_dgram_recv(int sock, uint8_t *buffer, size_t size, int timeout_ms)
+{
+ return net_base_recv(sock, buffer, size, NULL, timeout_ms);
+}
+
+ssize_t net_stream_send(int sock, const uint8_t *buffer, size_t size, int timeout_ms)
+{
+ return net_base_send(sock, buffer, size, NULL, timeout_ms);
+}
+
+ssize_t net_stream_recv(int sock, uint8_t *buffer, size_t size, int timeout_ms)
+{
+ return net_base_recv(sock, buffer, size, NULL, timeout_ms);
+}
+
+/* -- DNS specific I/O ----------------------------------------------------- */
+
+ssize_t net_dns_tcp_send(int sock, const uint8_t *buffer, size_t size, int timeout_ms,
+ struct sockaddr_storage *tfo_addr)
+{
+ if (sock < 0 || buffer == NULL || size > UINT16_MAX) {
+ return KNOT_EINVAL;
+ }
+
+ struct iovec iov[2];
+ uint16_t pktsize = htons(size);
+ iov[0].iov_base = &pktsize;
+ iov[0].iov_len = sizeof(uint16_t);
+ iov[1].iov_base = (void *)buffer;
+ iov[1].iov_len = size;
+
+ struct msghdr msg = { 0 };
+ msg.msg_iov = iov;
+ msg.msg_iovlen = 2;
+ msg.msg_name = (void *)tfo_addr;
+ msg.msg_namelen = tfo_addr ? sizeof(*tfo_addr) : 0;
+
+ ssize_t ret = send_data(sock, &msg, &timeout_ms, tfo_addr != NULL);
+ if (ret < 0) {
+ return ret;
+ }
+
+ return size; /* Do not count the size prefix. */
+}
+
+ssize_t net_dns_tcp_recv(int sock, uint8_t *buffer, size_t size, int timeout_ms)
+{
+ if (sock < 0 || buffer == NULL) {
+ return KNOT_EINVAL;
+ }
+
+ uint16_t pktsize = 0;
+
+ struct iovec iov = {
+ .iov_base = &pktsize,
+ .iov_len = sizeof(pktsize)
+ };
+ struct msghdr msg = {
+ .msg_iov = &iov,
+ .msg_iovlen = 1
+ };
+
+ /* Receive size. */
+ int ret = recv_data(sock, &msg, false, &timeout_ms);
+ if (ret != sizeof(pktsize)) {
+ return ret;
+ }
+ pktsize = ntohs(pktsize);
+
+ /* Check packet size */
+ if (size < pktsize) {
+ return KNOT_ESPACE;
+ }
+
+ /* Receive payload. */
+ iov.iov_base = buffer;
+ iov.iov_len = pktsize;
+
+ return recv_data(sock, &msg, false, &timeout_ms);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-03 00:42:03 +0000