MEDIUM: udp: adds minimal proto udp support for message listeners.
This patch introduce proto_udp.c targeting a further support of
log forwarding feature.
This code was originally produced by Frederic Lecaille working on
QUIC support and only minimal requirements for syslog support
have been merged.
diff --git a/src/proto_udp.c b/src/proto_udp.c
new file mode 100644
index 0000000..d006c45
--- /dev/null
+++ b/src/proto_udp.c
@@ -0,0 +1,388 @@
+/*
+ * AF_CUST_UDP/AF_CUST_UDP6 UDP protocol layer
+ *
+ * Copyright 2019 HAProxy Technologies, Frédéric Lécaille <flecaille@haproxy.com>
+ *
+ * Partial merge by Emeric Brun <ebrun@haproxy.com>
+ *
+ * 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
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#include <sys/param.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+
+#include <netinet/udp.h>
+#include <netinet/in.h>
+
+#include <haproxy/fd.h>
+#include <haproxy/listener.h>
+#include <haproxy/log.h>
+#include <haproxy/namespace.h>
+#include <haproxy/port_range.h>
+#include <haproxy/protocol.h>
+#include <haproxy/proto_udp.h>
+#include <haproxy/proxy.h>
+#include <haproxy/server.h>
+#include <haproxy/task.h>
+
+static int udp_bind_listeners(struct protocol *proto, char *errmsg, int errlen);
+static int udp_bind_listener(struct listener *listener, char *errmsg, int errlen);
+static void udp4_add_listener(struct listener *listener, int port);
+static void udp6_add_listener(struct listener *listener, int port);
+
+/* Note: must not be declared <const> as its list will be overwritten */
+static struct protocol proto_udp4 = {
+ .name = "udp4",
+ .sock_domain = AF_CUST_UDP4,
+ .sock_type = SOCK_DGRAM,
+ .sock_prot = IPPROTO_UDP,
+ .sock_family = AF_INET,
+ .sock_addrlen = sizeof(struct sockaddr_in),
+ .l3_addrlen = 32/8,
+ .accept = NULL,
+ .connect = NULL,
+ .bind = udp_bind_listener,
+ .bind_all = udp_bind_listeners,
+ .unbind_all = unbind_all_listeners,
+ .enable_all = enable_all_listeners,
+ .get_src = udp_get_src,
+ .get_dst = udp_get_dst,
+ .pause = udp_pause_listener,
+ .add = udp4_add_listener,
+ .listeners = LIST_HEAD_INIT(proto_udp4.listeners),
+ .nb_listeners = 0,
+};
+
+INITCALL1(STG_REGISTER, protocol_register, &proto_udp4);
+
+/* Note: must not be declared <const> as its list will be overwritten */
+static struct protocol proto_udp6 = {
+ .name = "udp6",
+ .sock_domain = AF_CUST_UDP6,
+ .sock_type = SOCK_DGRAM,
+ .sock_prot = IPPROTO_UDP,
+ .sock_family = AF_INET6,
+ .sock_addrlen = sizeof(struct sockaddr_in6),
+ .l3_addrlen = 128/8,
+ .accept = NULL,
+ .connect = NULL,
+ .bind = udp_bind_listener,
+ .bind_all = udp_bind_listeners,
+ .unbind_all = unbind_all_listeners,
+ .enable_all = enable_all_listeners,
+ .get_src = udp_get_src,
+ .get_dst = udp_get_dst,
+ .pause = udp_pause_listener,
+ .add = udp6_add_listener,
+ .listeners = LIST_HEAD_INIT(proto_udp6.listeners),
+ .nb_listeners = 0,
+};
+
+INITCALL1(STG_REGISTER, protocol_register, &proto_udp6);
+
+/*
+ * Retrieves the source address for the socket <fd>, with <dir> indicating
+ * if we're a listener (=0) or an initiator (!=0). It returns 0 in case of
+ * success, -1 in case of error. The socket's source address is stored in
+ * <sa> for <salen> bytes.
+ */
+int udp_get_src(int fd, struct sockaddr *sa, socklen_t salen, int dir)
+{
+ int ret;
+
+ if (dir)
+ ret = getsockname(fd, sa, &salen);
+ else
+ ret = getpeername(fd, sa, &salen);
+
+ if (!ret) {
+ if (sa->sa_family == AF_INET)
+ sa->sa_family = AF_CUST_UDP4;
+ else if (sa->sa_family == AF_INET6)
+ sa->sa_family = AF_CUST_UDP6;
+ }
+
+ return ret;
+}
+
+
+/*
+ * Retrieves the original destination address for the socket <fd>, with <dir>
+ * indicating if we're a listener (=0) or an initiator (!=0). In the case of a
+ * listener, if the original destination address was translated, the original
+ * address is retrieved. It returns 0 in case of success, -1 in case of error.
+ * The socket's source address is stored in <sa> for <salen> bytes.
+ */
+int udp_get_dst(int fd, struct sockaddr *sa, socklen_t salen, int dir)
+{
+ int ret;
+
+ if (dir)
+ ret = getpeername(fd, sa, &salen);
+ else {
+ ret = getsockname(fd, sa, &salen);
+
+ if (ret < 0)
+ return ret;
+
+#if defined(USE_TPROXY) && defined(SO_ORIGINAL_DST)
+ /* For TPROXY and Netfilter's NAT, we can retrieve the original
+ * IPv4 address before DNAT/REDIRECT. We must not do that with
+ * other families because v6-mapped IPv4 addresses are still
+ * reported as v4.
+ */
+ if (((struct sockaddr_storage *)sa)->ss_family == AF_INET
+ && getsockopt(fd, SOL_IP, SO_ORIGINAL_DST, sa, &salen) == 0) {
+ sa->sa_family = AF_CUST_UDP4;
+ return 0;
+ }
+#endif
+ }
+
+ if (!ret) {
+ if (sa->sa_family == AF_INET)
+ sa->sa_family = AF_CUST_UDP4;
+ else if (sa->sa_family == AF_INET6)
+ sa->sa_family = AF_CUST_UDP6;
+ }
+
+ return ret;
+}
+
+/* This function tries to bind a UDPv4/v6 listener. It may return a warning or
+ * an error message in <errmsg> if the message is at most <errlen> bytes long
+ * (including '\0'). Note that <errmsg> may be NULL if <errlen> is also zero.
+ * The return value is composed from ERR_ABORT, ERR_WARN,
+ * ERR_ALERT, ERR_RETRYABLE and ERR_FATAL. ERR_NONE indicates that everything
+ * was alright and that no message was returned. ERR_RETRYABLE means that an
+ * error occurred but that it may vanish after a retry (eg: port in use), and
+ * ERR_FATAL indicates a non-fixable error. ERR_WARN and ERR_ALERT do not alter
+ * the meaning of the error, but just indicate that a message is present which
+ * should be displayed with the respective level. Last, ERR_ABORT indicates
+ * that it's pointless to try to start other listeners. No error message is
+ * returned if errlen is NULL.
+ */
+int udp_bind_listener(struct listener *listener, char *errmsg, int errlen)
+{
+ __label__ udp_return, udp_close_return;
+ int fd, err;
+ const char *msg = NULL;
+ /* copy listener addr because sometimes we need to switch family */
+ struct sockaddr_storage addr_inet = listener->addr;
+
+ /* force to classic sock family */
+ addr_inet.ss_family = listener->proto->sock_family;
+
+ /* ensure we never return garbage */
+ if (errlen)
+ *errmsg = 0;
+
+ if (listener->state != LI_ASSIGNED)
+ return ERR_NONE; /* already bound */
+
+ err = ERR_NONE;
+
+ /* TODO: Implement reuse fd. Take care that to identify fd to reuse
+ * listeners uses a special AF_CUST_ family and we MUST consider
+ * IPPROTO (sockaddr is not enought
+ */
+
+ fd = my_socketat(listener->netns, listener->proto->sock_family, listener->proto->sock_type, listener->proto->sock_prot);
+ if (fd == -1) {
+ err |= ERR_RETRYABLE | ERR_ALERT;
+ msg = "cannot create listening socket";
+ goto udp_return;
+ }
+
+ if (fd >= global.maxsock) {
+ err |= ERR_FATAL | ERR_ABORT | ERR_ALERT;
+ msg = "not enough free sockets (raise '-n' parameter)";
+ goto udp_close_return;
+ }
+
+ if (fcntl(fd, F_SETFL, O_NONBLOCK) == -1) {
+ err |= ERR_FATAL | ERR_ALERT;
+ msg = "cannot make socket non-blocking";
+ goto udp_close_return;
+ }
+
+ if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)) == -1) {
+ /* not fatal but should be reported */
+ msg = "cannot do so_reuseaddr";
+ err |= ERR_ALERT;
+ }
+
+#ifdef SO_REUSEPORT
+ /* OpenBSD and Linux 3.9 support this. As it's present in old libc versions of
+ * Linux, it might return an error that we will silently ignore.
+ */
+ if (global.tune.options & GTUNE_USE_REUSEPORT)
+ setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &one, sizeof(one));
+#endif
+
+ if (listener->options & LI_O_FOREIGN) {
+ switch (addr_inet.ss_family) {
+ case AF_INET:
+ if (1
+#if defined(IP_TRANSPARENT)
+ && (setsockopt(fd, SOL_IP, IP_TRANSPARENT, &one, sizeof(one)) == -1)
+#endif
+#if defined(IP_FREEBIND)
+ && (setsockopt(fd, SOL_IP, IP_FREEBIND, &one, sizeof(one)) == -1)
+#endif
+#if defined(IP_BINDANY)
+ && (setsockopt(fd, IPPROTO_IP, IP_BINDANY, &one, sizeof(one)) == -1)
+#endif
+#if defined(SO_BINDANY)
+ && (setsockopt(fd, SOL_SOCKET, SO_BINDANY, &one, sizeof(one)) == -1)
+#endif
+ ) {
+ msg = "cannot make listening socket transparent";
+ err |= ERR_ALERT;
+ }
+ break;
+ case AF_INET6:
+ if (1
+#if defined(IPV6_TRANSPARENT) && defined(SOL_IPV6)
+ && (setsockopt(fd, SOL_IPV6, IPV6_TRANSPARENT, &one, sizeof(one)) == -1)
+#endif
+#if defined(IP_FREEBIND)
+ && (setsockopt(fd, SOL_IP, IP_FREEBIND, &one, sizeof(one)) == -1)
+#endif
+#if defined(IPV6_BINDANY)
+ && (setsockopt(fd, IPPROTO_IPV6, IPV6_BINDANY, &one, sizeof(one)) == -1)
+#endif
+#if defined(SO_BINDANY)
+ && (setsockopt(fd, SOL_SOCKET, SO_BINDANY, &one, sizeof(one)) == -1)
+#endif
+ ) {
+ msg = "cannot make listening socket transparent";
+ err |= ERR_ALERT;
+ }
+ break;
+ }
+ }
+
+#ifdef SO_BINDTODEVICE
+ /* Note: this might fail if not CAP_NET_RAW */
+ if (listener->interface) {
+ if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE,
+ listener->interface, strlen(listener->interface) + 1) == -1) {
+ msg = "cannot bind listener to device";
+ err |= ERR_WARN;
+ }
+ }
+#endif
+#if defined(IPV6_V6ONLY)
+ if (listener->options & LI_O_V6ONLY)
+ setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one));
+ else if (listener->options & LI_O_V4V6)
+ setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &zero, sizeof(zero));
+#endif
+
+ if (bind(fd, (struct sockaddr *)&addr_inet, listener->proto->sock_addrlen) < 0) {
+ err |= ERR_RETRYABLE | ERR_ALERT;
+ msg = "cannot bind socket";
+ goto udp_close_return;
+ }
+
+ /* the socket is ready */
+ listener->fd = fd;
+ listener->state = LI_LISTEN;
+
+ err |= ERR_FATAL | ERR_ALERT;
+ msg = "UDP is not yet supported on this proxy mode";
+ goto udp_close_return;
+
+ udp_return:
+ if (msg && errlen) {
+ char pn[INET6_ADDRSTRLEN];
+
+ addr_to_str(&addr_inet, pn, sizeof(pn));
+ snprintf(errmsg, errlen, "%s [%s:%d]", msg, pn, get_host_port(&addr_inet));
+ }
+ return err;
+
+ udp_close_return:
+ close(fd);
+ goto udp_return;
+}
+
+/* This function creates all UDP sockets bound to the protocol entry <proto>.
+ * It is intended to be used as the protocol's bind_all() function.
+ * The sockets will be registered but not added to any fd_set, in order not to
+ * loose them across the fork(). A call to enable_all_listeners() is needed
+ * to complete initialization. The return value is composed from ERR_*.
+ */
+static int udp_bind_listeners(struct protocol *proto, char *errmsg, int errlen)
+{
+ struct listener *listener;
+ int err = ERR_NONE;
+
+ list_for_each_entry(listener, &proto->listeners, proto_list) {
+ err |= udp_bind_listener(listener, errmsg, errlen);
+ if (err & ERR_ABORT)
+ break;
+ }
+
+ return err;
+}
+
+/* Add <listener> to the list of udp4 listeners, on port <port>. The
+ * listener's state is automatically updated from LI_INIT to LI_ASSIGNED.
+ * The number of listeners for the protocol is updated.
+ */
+static void udp4_add_listener(struct listener *listener, int port)
+{
+ if (listener->state != LI_INIT)
+ return;
+ listener->state = LI_ASSIGNED;
+ listener->proto = &proto_udp4;
+ ((struct sockaddr_in *)(&listener->addr))->sin_port = htons(port);
+ LIST_ADDQ(&proto_udp4.listeners, &listener->proto_list);
+ proto_udp4.nb_listeners++;
+}
+
+/* Add <listener> to the list of udp6 listeners, on port <port>. The
+ * listener's state is automatically updated from LI_INIT to LI_ASSIGNED.
+ * The number of listeners for the protocol is updated.
+ */
+static void udp6_add_listener(struct listener *listener, int port)
+{
+ if (listener->state != LI_INIT)
+ return;
+ listener->state = LI_ASSIGNED;
+ listener->proto = &proto_udp6;
+ ((struct sockaddr_in *)(&listener->addr))->sin_port = htons(port);
+ LIST_ADDQ(&proto_udp6.listeners, &listener->proto_list);
+ proto_udp6.nb_listeners++;
+}
+
+/* Pause a listener. Returns < 0 in case of failure, 0 if the listener
+ * was totally stopped, or > 0 if correctly paused.
+ */
+int udp_pause_listener(struct listener *l)
+{
+ /* we don't support pausing on UDP */
+ return -1;
+}
+
+/*
+ * Local variables:
+ * c-indent-level: 8
+ * c-basic-offset: 8
+ * End:
+ */