/* * include/types/connection.h * This file describes the connection struct and associated constants. * * Copyright (C) 2000-2012 Willy Tarreau - w@1wt.eu * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation, version 2.1 * exclusively. * * This library 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #ifndef _TYPES_CONNECTION_H #define _TYPES_CONNECTION_H #include #include #include #include #include /* referenced below */ struct connection; struct buffer; struct pipe; struct server; struct proxy; struct si_applet; struct task; /* Polling flags that are manipulated by I/O callbacks and handshake callbacks * indicate what they expect from a file descriptor at each layer. For each * direction, we have 2 bits, one stating whether any suspected activity on the * FD induce a call to the iocb, and another one indicating that the FD has * already returned EAGAIN and that polling on it is essential before calling * the iocb again : * POL ENA state * 0 0 STOPPED : any activity on this FD is ignored * 0 1 ENABLED : any (suspected) activity may call the iocb * 1 0 STOPPED : as above * 1 1 POLLED : the FD is being polled for activity * * - Enabling an I/O event consists in ORing with 1. * - Stopping an I/O event consists in ANDing with ~1. * - Polling for an I/O event consists in ORing with ~3. * * The last computed state is remembered in CO_FL_CURR_* so that differential * changes can be applied. After bits are applied, the POLL status bits are * cleared so that it is possible to detect when an EAGAIN was encountered. For * pollers that do not support speculative I/O, POLLED is the same as ENABLED * and the POL flag can safely be ignored. However it makes a difference for * the connection handler. * * The ENA flags are per-layer (one pair for SOCK, another one for DATA). * The POL flags are only for the socket layer since they indicate that EAGAIN * was encountered. Thus, the DATA layer uses its own ENA flag and the socket * layer's POL flag. * * The bits are arranged so that it is possible to detect a change by performing * only a left shift followed by a xor and applying a mask to the result. The * principle is that depending on what we want to check (data polling changes or * sock polling changes), we mask different bits. The bits are arranged this way : * * S(ock) - W(ait) - C(urr) - P(oll) - D(ata) * * SOCK changes are reported when (S != C) || (W != P) => (S:W) != (C:P) * DATA changes are reported when (D != C) || (W != P) => (W:C) != (P:D) * The R and W bits are split apart so that we never shift more than 2 bits at * a time, allowing move+shift to be done as a single operation on x86. */ /* flags for use in connection->flags */ enum { CO_FL_NONE = 0x00000000, /* Just for initialization purposes */ /* Do not change these values without updating conn_*_poll_changes() ! */ CO_FL_DATA_RD_ENA = 0x00000001, /* receiving data is allowed */ CO_FL_CURR_RD_POL = 0x00000002, /* receiving needs to poll first */ CO_FL_CURR_RD_ENA = 0x00000004, /* receiving is currently allowed */ CO_FL_WAIT_RD = 0x00000008, /* receiving needs to poll first */ CO_FL_SOCK_RD_ENA = 0x00000010, /* receiving handshakes is allowed */ CO_FL_DATA_WR_ENA = 0x00000020, /* sending data is desired */ CO_FL_CURR_WR_POL = 0x00000040, /* sending needs to poll first */ CO_FL_CURR_WR_ENA = 0x00000080, /* sending is currently desired */ CO_FL_WAIT_WR = 0x00000100, /* sending needs to poll first */ CO_FL_SOCK_WR_ENA = 0x00000200, /* sending handshakes is desired */ /* These flags are used by data layers to indicate they had to stop * sending data because a buffer was empty (WAIT_DATA) or stop receiving * data because a buffer was full (WAIT_ROOM). The connection handler * clears them before first calling the I/O and data callbacks. */ CO_FL_WAIT_DATA = 0x00000400, /* data source is empty */ CO_FL_WAIT_ROOM = 0x00000800, /* data sink is full */ /* These flags are used to report whether the from/to addresses are set or not */ CO_FL_ADDR_FROM_SET = 0x00001000, /* addr.from is set */ CO_FL_ADDR_TO_SET = 0x00002000, /* addr.to is set */ /* flags indicating what event type the data layer is interested in */ CO_FL_INIT_DATA = 0x00004000, /* initialize the data layer before using it */ CO_FL_WAKE_DATA = 0x00008000, /* wake-up data layer upon activity at the transport layer */ /* flags used to remember what shutdown have been performed/reported */ CO_FL_DATA_RD_SH = 0x00010000, /* DATA layer was notified about shutr/read0 */ CO_FL_DATA_WR_SH = 0x00020000, /* DATA layer asked for shutw */ CO_FL_SOCK_RD_SH = 0x00040000, /* SOCK layer was notified about shutr/read0 */ CO_FL_SOCK_WR_SH = 0x00080000, /* SOCK layer asked for shutw */ /* flags used to report connection status and errors */ CO_FL_ERROR = 0x00100000, /* a fatal error was reported */ CO_FL_CONNECTED = 0x00200000, /* the connection is now established */ CO_FL_WAIT_L4_CONN = 0x00400000, /* waiting for L4 to be connected */ CO_FL_WAIT_L6_CONN = 0x00800000, /* waiting for L6 to be connected (eg: SSL) */ /* synthesis of the flags above */ CO_FL_CONN_STATE = 0x00FF0000, /* all shut/connected flags */ /*** All the flags below are used for connection handshakes. Any new * handshake should be added after this point, and CO_FL_HANDSHAKE * should be updated. */ CO_FL_SI_SEND_PROXY = 0x01000000, /* send a valid PROXY protocol header */ CO_FL_SSL_WAIT_HS = 0x02000000, /* wait for an SSL handshake to complete */ CO_FL_ACCEPT_PROXY = 0x04000000, /* receive a valid PROXY protocol header */ CO_FL_LOCAL_SPROXY = 0x08000000, /* send a valid local PROXY protocol header */ /* below we have all handshake flags grouped into one */ CO_FL_HANDSHAKE = CO_FL_SI_SEND_PROXY | CO_FL_SSL_WAIT_HS | CO_FL_ACCEPT_PROXY | CO_FL_LOCAL_SPROXY, /* when any of these flags is set, polling is defined by socket-layer * operations, as opposed to data-layer. Transport is explicitly not * mentionned here to avoid any confusion, since it can be the same * as DATA or SOCK on some implementations. */ CO_FL_POLL_SOCK = CO_FL_HANDSHAKE | CO_FL_WAIT_L4_CONN | CO_FL_WAIT_L6_CONN, /* This last flag indicates that the transport layer is used (for instance * by logs) and must not be cleared yet. The last call to conn_xprt_close() * must be done after clearing this flag. */ CO_FL_XPRT_TRACKED = 0x80000000, }; /* target types */ enum { TARG_TYPE_NONE = 0, /* no target set, pointer is NULL by definition */ TARG_TYPE_CLIENT, /* target is a client, pointer is NULL by definition */ TARG_TYPE_PROXY, /* target is a proxy ; use address with the proxy's settings */ TARG_TYPE_SERVER, /* target is a server ; use address with server's and its proxy's settings */ TARG_TYPE_APPLET, /* target is an applet ; use only the applet */ TARG_TYPE_TASK, /* target is a task running an external applet */ }; /* xprt_ops describes transport-layer operations for a connection. They * generally run over a socket-based control layer, but not always. Some * of them are used for data transfer with the upper layer (rcv_*, snd_*) * and the other ones are used to setup and release the transport layer. */ struct xprt_ops { int (*rcv_buf)(struct connection *conn, struct buffer *buf, int count); /* recv callback */ int (*snd_buf)(struct connection *conn, struct buffer *buf, int flags); /* send callback */ int (*rcv_pipe)(struct connection *conn, struct pipe *pipe, unsigned int count); /* recv-to-pipe callback */ int (*snd_pipe)(struct connection *conn, struct pipe *pipe); /* send-to-pipe callback */ void (*shutr)(struct connection *, int); /* shutr function */ void (*shutw)(struct connection *, int); /* shutw function */ void (*close)(struct connection *); /* close the transport layer */ int (*init)(struct connection *conn); /* initialize the transport layer */ }; /* data_cb describes the data layer's recv and send callbacks which are called * when I/O activity was detected after the transport layer is ready. These * callbacks are supposed to make use of the xprt_ops above to exchange data * from/to buffers and pipes. The callback is used to report activity * at the transport layer, which can be a connection opening/close, or any * data movement. The callback may be called by the connection handler * at the end of a transport handshake, when it is about to transfer data and * the data layer is not ready yet. Both and may abort a connection * by returning < 0. */ struct data_cb { void (*recv)(struct connection *conn); /* data-layer recv callback */ void (*send)(struct connection *conn); /* data-layer send callback */ int (*wake)(struct connection *conn); /* data-layer callback to report activity */ int (*init)(struct connection *conn); /* data-layer initialization */ }; /* a target describes what is on the remote side of the connection. */ struct target { int type; union { void *v; /* pointer value, for any type */ struct proxy *p; /* when type is TARG_TYPE_PROXY */ struct server *s; /* when type is TARG_TYPE_SERVER */ struct si_applet *a; /* when type is TARG_TYPE_APPLET */ struct task *t; /* when type is TARG_TYPE_TASK */ struct listener *l; /* when type is TARG_TYPE_CLIENT */ } ptr; } __attribute__((packed)); /* This structure describes a connection with its methods and data. * A connection may be performed to proxy or server via a local or remote * socket, and can also be made to an internal applet. It can support * several transport schemes (applet, raw, ssl, ...). It can support several * connection control schemes, generally a protocol for socket-oriented * connections, but other methods for applets. */ struct connection { const struct protocol *ctrl; /* operations at the socket layer */ const struct xprt_ops *xprt; /* operations at the transport layer */ const struct data_cb *data; /* data layer callbacks */ unsigned int flags; /* CO_F_* */ int xprt_st; /* transport layer state, initialized to zero */ void *xprt_ctx; /* general purpose pointer, initialized to NULL */ void *owner; /* pointer to upper layer's entity (eg: stream interface) */ union { /* definitions which depend on connection type */ struct { /*** information used by socket-based connections ***/ int fd; /* file descriptor for a stream driver when known */ } sock; } t; struct target target; /* the target to connect to (server, proxy, applet, ...) */ struct { struct sockaddr_storage from; /* client address, or address to spoof when connecting to the server */ struct sockaddr_storage to; /* address reached by the client, or address to connect to */ } addr; /* addresses of the remote side, client for producer and server for consumer */ }; #endif /* _TYPES_CONNECTION_H */ /* * Local variables: * c-indent-level: 8 * c-basic-offset: 8 * End: */