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-rw-r--r--src/proto_udp.c247
1 files changed, 247 insertions, 0 deletions
diff --git a/src/proto_udp.c b/src/proto_udp.c
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+/*
+ * UDP protocol layer on top of AF_INET/AF_INET6
+ *
+ * Copyright 2019 HAProxy Technologies, Frederic Lecaille <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 <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/sock.h>
+#include <haproxy/sock_inet.h>
+#include <haproxy/task.h>
+#include <haproxy/tools.h>
+
+static int udp_bind_listener(struct listener *listener, char *errmsg, int errlen);
+static void udp_enable_listener(struct listener *listener);
+static void udp_disable_listener(struct listener *listener);
+
+/* Note: must not be declared <const> as its list will be overwritten */
+struct protocol proto_udp4 = {
+ .name = "udp4",
+
+ /* connection layer */
+ .xprt_type = PROTO_TYPE_DGRAM,
+ .listen = udp_bind_listener,
+ .enable = udp_enable_listener,
+ .disable = udp_disable_listener,
+ .add = default_add_listener,
+ .unbind = default_unbind_listener,
+ .suspend = default_suspend_listener,
+ .resume = default_resume_listener,
+
+ /* binding layer */
+ .rx_suspend = udp_suspend_receiver,
+ .rx_resume = udp_resume_receiver,
+
+ /* address family */
+ .fam = &proto_fam_inet4,
+
+ /* socket layer */
+ .proto_type = PROTO_TYPE_DGRAM,
+ .sock_type = SOCK_DGRAM,
+ .sock_prot = IPPROTO_UDP,
+ .rx_enable = sock_enable,
+ .rx_disable = sock_disable,
+ .rx_unbind = sock_unbind,
+ .receivers = LIST_HEAD_INIT(proto_udp4.receivers),
+ .nb_receivers = 0,
+#ifdef SO_REUSEPORT
+ .flags = PROTO_F_REUSEPORT_SUPPORTED,
+#endif
+};
+
+INITCALL1(STG_REGISTER, protocol_register, &proto_udp4);
+
+/* Note: must not be declared <const> as its list will be overwritten */
+struct protocol proto_udp6 = {
+ .name = "udp6",
+
+ /* connection layer */
+ .xprt_type = PROTO_TYPE_DGRAM,
+ .listen = udp_bind_listener,
+ .enable = udp_enable_listener,
+ .disable = udp_disable_listener,
+ .add = default_add_listener,
+ .unbind = default_unbind_listener,
+ .suspend = default_suspend_listener,
+ .resume = default_resume_listener,
+
+ /* binding layer */
+ .rx_suspend = udp_suspend_receiver,
+ .rx_resume = udp_resume_receiver,
+
+ /* address family */
+ .fam = &proto_fam_inet6,
+
+ /* socket layer */
+ .proto_type = PROTO_TYPE_DGRAM,
+ .sock_type = SOCK_DGRAM,
+ .sock_prot = IPPROTO_UDP,
+ .rx_enable = sock_enable,
+ .rx_disable = sock_disable,
+ .rx_unbind = sock_unbind,
+ .receivers = LIST_HEAD_INIT(proto_udp6.receivers),
+ .nb_receivers = 0,
+#ifdef SO_REUSEPORT
+ .flags = PROTO_F_REUSEPORT_SUPPORTED,
+#endif
+};
+
+INITCALL1(STG_REGISTER, protocol_register, &proto_udp6);
+
+/* 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)
+{
+ int err = ERR_NONE;
+ char *msg = NULL;
+
+ /* ensure we never return garbage */
+ if (errlen)
+ *errmsg = 0;
+
+ if (listener->state != LI_ASSIGNED)
+ return ERR_NONE; /* already bound */
+
+ if (!(listener->rx.flags & RX_F_BOUND)) {
+ msg = "receiving socket not bound";
+ goto udp_return;
+ }
+
+ /* we may want to adjust the output buffer (tune.sndbuf.backend) */
+ if (global.tune.frontend_rcvbuf)
+ setsockopt(listener->rx.fd, SOL_SOCKET, SO_RCVBUF, &global.tune.frontend_rcvbuf, sizeof(global.tune.frontend_rcvbuf));
+
+ if (global.tune.frontend_sndbuf)
+ setsockopt(listener->rx.fd, SOL_SOCKET, SO_SNDBUF, &global.tune.frontend_sndbuf, sizeof(global.tune.frontend_sndbuf));
+
+ listener_set_state(listener, LI_LISTEN);
+
+ udp_return:
+ if (msg && errlen) {
+ char pn[INET6_ADDRSTRLEN];
+
+ addr_to_str(&listener->rx.addr, pn, sizeof(pn));
+ snprintf(errmsg, errlen, "%s for [%s:%d]", msg, pn, get_host_port(&listener->rx.addr));
+ }
+ return err;
+}
+
+/* Enable receipt of incoming connections for listener <l>. The receiver must
+ * still be valid.
+ */
+static void udp_enable_listener(struct listener *l)
+{
+ fd_want_recv_safe(l->rx.fd);
+}
+
+/* Disable receipt of incoming connections for listener <l>. The receiver must
+ * still be valid.
+ */
+static void udp_disable_listener(struct listener *l)
+{
+ fd_stop_recv(l->rx.fd);
+}
+
+/* Suspend a receiver. Returns < 0 in case of failure, 0 if the receiver
+ * was totally stopped, or > 0 if correctly suspended.
+ * The principle is a bit ugly but works well, at least on Linux: in order to
+ * suspend the receiver, we want it to stop receiving traffic, which means that
+ * the socket must be unhashed from the kernel's socket table. The simple way
+ * to do this is to connect to any address that is reachable and will not be
+ * used by regular traffic, and a great one is reconnecting to self. Note that
+ * inherited FDs are neither suspended nor resumed, we only enable/disable
+ * polling on them.
+ */
+int udp_suspend_receiver(struct receiver *rx)
+{
+ struct sockaddr_storage ss;
+ socklen_t len = sizeof(ss);
+
+ if (rx->fd < 0)
+ return 0;
+
+ /* we never do that with a shared FD otherwise we'd break it in the
+ * parent process and any possible subsequent worker inheriting it.
+ */
+ if (rx->flags & RX_F_INHERITED)
+ goto done;
+
+ if (getsockname(rx->fd, (struct sockaddr *)&ss, &len) < 0)
+ return -1;
+
+ if (connect(rx->fd, (struct sockaddr *)&ss, len) < 0)
+ return -1;
+ done:
+ /* not necessary but may make debugging clearer */
+ fd_stop_recv(rx->fd);
+ return 1;
+}
+
+/* Resume a receiver. Returns < 0 in case of failure, 0 if the receiver
+ * was totally stopped, or > 0 if correctly suspended.
+ * The principle is to reverse the change above, we'll break the connection by
+ * connecting to AF_UNSPEC. The association breaks and the socket starts to
+ * receive from everywhere again. Note that inherited FDs are neither suspended
+ * nor resumed, we only enable/disable polling on them.
+ */
+int udp_resume_receiver(struct receiver *rx)
+{
+ const struct sockaddr sa = { .sa_family = AF_UNSPEC };
+
+ if (rx->fd < 0)
+ return 0;
+
+ if (!(rx->flags & RX_F_INHERITED) && connect(rx->fd, &sa, sizeof(sa)) < 0)
+ return -1;
+
+ fd_want_recv(rx->fd);
+ return 1;
+}
+
+/*
+ * Local variables:
+ * c-indent-level: 8
+ * c-basic-offset: 8
+ * End:
+ */
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