diff options
author | Kip Macy <kmacy@FreeBSD.org> | 2007-12-17 07:56:27 +0000 |
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committer | Kip Macy <kmacy@FreeBSD.org> | 2007-12-17 07:56:27 +0000 |
commit | 8b5709dfabd4d4889e1866188b19f6114327ed69 (patch) | |
tree | b9000c4541f5e9666b6711cf6933c727f6eb15b1 /sys/netinet/tcp_offload.h | |
parent | 29910a5a77c2902cf80841a74a9446576dc19a17 (diff) | |
download | src-8b5709dfabd4d4889e1866188b19f6114327ed69.tar.gz src-8b5709dfabd4d4889e1866188b19f6114327ed69.zip |
Notes
Diffstat (limited to 'sys/netinet/tcp_offload.h')
-rw-r--r-- | sys/netinet/tcp_offload.h | 328 |
1 files changed, 328 insertions, 0 deletions
diff --git a/sys/netinet/tcp_offload.h b/sys/netinet/tcp_offload.h new file mode 100644 index 000000000000..33d73ee553af --- /dev/null +++ b/sys/netinet/tcp_offload.h @@ -0,0 +1,328 @@ +/*- + * Copyright (c) 2007, Chelsio Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * 2. Neither the name of the Chelsio Corporation nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + * $FreeBSD$ + */ + +#ifndef _NETINET_TCP_OFFLOAD_H_ +#define _NETINET_TCP_OFFLOAD_H_ + +#ifndef _KERNEL +#error "no user-serviceable parts inside" +#endif + +/* + * A driver publishes that it provides offload services + * by setting IFCAP_TOE in the ifnet. The offload connect + * will bypass any further work if the interface that a + * connection would use does not support TCP offload. + * + * The TOE API assumes that the tcp offload engine can offload the + * the entire connection from set up to teardown, with some provision + * being made to allowing the software stack to handle time wait. If + * the device does not meet these criteria, it is the driver's responsibility + * to overload the functions that it needs to in tcp_usrreqs and make + * its own calls to tcp_output if it needs to do so. + * + * There is currently no provision for the device advertising the congestion + * control algorithms it supports as there is currently no API for querying + * an operating system for the protocols that it has loaded. This is a desirable + * future extension. + * + * + * + * It is assumed that individuals deploying TOE will want connections + * to be offloaded without software changes so all connections on an + * interface providing TOE are offloaded unless the the SO_NO_OFFLOAD + * flag is set on the socket. + * + * + * The toe_usrreqs structure constitutes the TOE driver's + * interface to the TCP stack for functionality that doesn't + * interact directly with userspace. If one wants to provide + * (optional) functionality to do zero-copy to/from + * userspace one still needs to override soreceive/sosend + * with functions that fault in and pin the user buffers. + * + * + tu_send + * - tells the driver that new data may have been added to the + * socket's send buffer - the driver should not fail if the + * buffer is in fact unchanged + * - the driver is responsible for providing credits (bytes in the send window) + * back to the socket by calling sbdrop() as segments are acknowledged. + * - The driver expects the inpcb lock to be held - the driver is expected + * not to drop the lock. Hence the driver is not allowed to acquire the + * pcbinfo lock during this call. + * + * + tu_rcvd + * - returns credits to the driver and triggers window updates + * to the peer (a credit as used here is a byte in the peer's receive window) + * - the driver is expected to determine how many bytes have been + * consumed and credit that back to the card so that it can grow + * the window again by maintaining its own state between invocations. + * - In principle this could be used to shrink the window as well as + * grow the window, although it is not used for that now. + * - this function needs to correctly handle being called any number of + * times without any bytes being consumed from the receive buffer. + * - The driver expects the inpcb lock to be held - the driver is expected + * not to drop the lock. Hence the driver is not allowed to acquire the + * pcbinfo lock during this call. + * + * + tu_disconnect + * - tells the driver to send FIN to peer + * - driver is expected to send the remaining data and then do a clean half close + * - disconnect implies at least half-close so only send, reset, and detach + * are legal + * - the driver is expected to handle transition through the shutdown + * state machine and allow the stack to support SO_LINGER. + * - The driver expects the inpcb lock to be held - the driver is expected + * not to drop the lock. Hence the driver is not allowed to acquire the + * pcbinfo lock during this call. + * + * + tu_reset + * - closes the connection and sends a RST to peer + * - driver is expectd to trigger an RST and detach the toepcb + * - no further calls are legal after reset + * - The driver expects the inpcb lock to be held - the driver is expected + * not to drop the lock. Hence the driver is not allowed to acquire the + * pcbinfo lock during this call. + * + * The following fields in the tcpcb are expected to be referenced by the driver: + * + iss + * + rcv_nxt + * + rcv_wnd + * + snd_isn + * + snd_max + * + snd_nxt + * + snd_una + * + t_flags + * + t_inpcb + * + t_maxseg + * + t_toe + * + * The following fields in the inpcb are expected to be referenced by the driver: + * + inp_lport + * + inp_fport + * + inp_laddr + * + inp_fport + * + inp_socket + * + inp_ip_tos + * + * The following fields in the socket are expected to be referenced by the + * driver: + * + so_comp + * + so_error + * + so_linger + * + so_options + * + so_rcv + * + so_snd + * + so_state + * + so_timeo + * + * These functions all return 0 on success and can return the following errors + * as appropriate: + * + EPERM: + * + ENOBUFS: memory allocation failed + * + EMSGSIZE: MTU changed during the call + * + EHOSTDOWN: + * + EHOSTUNREACH: + * + ENETDOWN: + * * ENETUNREACH: the peer is no longer reachable + * + * + tu_detach + * - tells driver that the socket is going away so disconnect + * the toepcb and free appropriate resources + * - allows the driver to cleanly handle the case of connection state + * outliving the socket + * - no further calls are legal after detach + * - the driver is expected to provide its own synchronization between + * detach and receiving new data. + * + * + tu_syncache_event + * - even if it is not actually needed, the driver is expected to + * call syncache_add for the initial SYN and then syncache_expand + * for the SYN,ACK + * - tells driver that a connection either has not been added or has + * been dropped from the syncache + * - the driver is expected to maintain state that lives outside the + * software stack so the syncache needs to be able to notify the + * toe driver that the software stack is not going to create a connection + * for a received SYN + * - The driver is responsible for any synchronization required between + * the syncache dropping an entry and the driver processing the SYN,ACK. + * + */ +struct toe_usrreqs { + int (*tu_send)(struct tcpcb *tp); + int (*tu_rcvd)(struct tcpcb *tp); + int (*tu_disconnect)(struct tcpcb *tp); + int (*tu_reset)(struct tcpcb *tp); + void (*tu_detach)(struct tcpcb *tp); + void (*tu_syncache_event)(int event, void *toep); +}; + +#define TOE_SC_ENTRY_PRESENT 1 /* 4-tuple already present */ +#define TOE_SC_DROP 2 /* connection was timed out */ + +/* + * Because listen is a one-to-many relationship (a socket can be listening + * on all interfaces on a machine some of which may be using different TCP + * offload devices), listen uses a publish/subscribe mechanism. The TCP + * offload driver registers a listen notification function with the stack. + * When a listen socket is created all TCP offload devices are notified + * so that they can do the appropriate set up to offload connections on the + * port to which the socket is bound. When the listen socket is closed, + * the offload devices are notified so that they will stop listening on that + * port and free any associated resources as well as sending RSTs on any + * connections in the SYN_RCVD state. + * + */ + +typedef void (*tcp_offload_listen_start_fn)(void *, struct tcpcb *); +typedef void (*tcp_offload_listen_stop_fn)(void *, struct tcpcb *); + +EVENTHANDLER_DECLARE(tcp_offload_listen_start, tcp_offload_listen_start_fn); +EVENTHANDLER_DECLARE(tcp_offload_listen_stop, tcp_offload_listen_stop_fn); + +/* + * Check if the socket can be offloaded by the following steps: + * - determine the egress interface + * - check the interface for TOE capability and TOE is enabled + * - check if the device has resources to offload the connection + */ +int tcp_offload_connect(struct socket *so, struct sockaddr *nam); + +/* + * The tcp_gen_* routines are wrappers around the toe_usrreqs calls, + * in the non-offloaded case they translate to tcp_output. + * + * Listen is a special case because it is a 1 to many relationship + * and there can be more than one offload driver in the system. + */ + +/* + * Connection is offloaded + */ +#define tp_offload(tp) ((tp)->t_flags & TF_TOE) +/* + * The socket has not been marked as "do not offload" + */ +#define SO_OFFLOADABLE(so) ((so->so_options & SO_NO_OFFLOAD) == 0) + +static __inline int +tcp_gen_connect(struct socket *so, struct sockaddr *nam) +{ + struct tcpcb *tp = sototcpcb(so); + int error; + + /* + * If offload has been disabled for this socket or the + * connection cannot be offloaded just call tcp_output + * to start the TCP state machine. + */ +#ifndef TCP_OFFLOAD_DISABLE + if (!SO_OFFLOADABLE(so) || (error = tcp_offload_connect(so, nam)) != 0) +#endif + error = tcp_output(tp); + return (error); +} + +static __inline int +tcp_gen_send(struct tcpcb *tp) +{ + +#ifndef TCP_OFFLOAD_DISABLE + if (tp_offload(tp)) + return (tp->t_tu->tu_send(tp)); +#endif + return (tcp_output(tp)); +} + +static __inline int +tcp_gen_rcvd(struct tcpcb *tp) +{ + +#ifndef TCP_OFFLOAD_DISABLE + if (tp_offload(tp)) + return (tp->t_tu->tu_rcvd(tp)); +#endif + return (tcp_output(tp)); +} + +static __inline int +tcp_gen_disconnect(struct tcpcb *tp) +{ + +#ifndef TCP_OFFLOAD_DISABLE + if (tp_offload(tp)) + return (tp->t_tu->tu_disconnect(tp)); +#endif + return (tcp_output(tp)); +} + +static __inline int +tcp_gen_reset(struct tcpcb *tp) +{ + +#ifndef TCP_OFFLOAD_DISABLE + if (tp_offload(tp)) + return (tp->t_tu->tu_reset(tp)); +#endif + return (tcp_output(tp)); +} + +static __inline void +tcp_gen_detach(struct tcpcb *tp) +{ + +#ifndef TCP_OFFLOAD_DISABLE + if (tp_offload(tp)) + tp->t_tu->tu_detach(tp); +#endif +} + +static __inline void +tcp_gen_listen_open(struct tcpcb *tp) +{ + +#ifndef TCP_OFFLOAD_DISABLE + if (SO_OFFLOADABLE(tp->t_inpcb->inp_socket)) + EVENTHANDLER_INVOKE(tcp_offload_listen_start, tp); +#endif +} + +static __inline void +tcp_gen_listen_close(struct tcpcb *tp) +{ + +#ifndef TCP_OFFLOAD_DISABLE + EVENTHANDLER_INVOKE(tcp_offload_listen_stop, tp); +#endif +} + +#undef tp_offload +#undef SO_OFFLOADABLE +#endif /* _NETINET_TCP_OFFLOAD_H_ */ |