diff options
Diffstat (limited to 'src/proto_udp.c')
| -rw-r--r-- | src/proto_udp.c | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/src/proto_udp.c b/src/proto_udp.c new file mode 100644 index 0000000..1fd92c7 --- /dev/null +++ b/src/proto_udp.c @@ -0,0 +1,234 @@ +/* + * 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, +}; + +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, +}; + +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; + } + + 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: + */ |