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linux/net/rxrpc/ar-output.c

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/* RxRPC packet transmission
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.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 <linux/net.h>
#include <linux/skbuff.h>
#include <linux/circ_buf.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include "ar-internal.h"
int rxrpc_resend_timeout = 4;
static int rxrpc_send_data(struct kiocb *iocb,
struct rxrpc_sock *rx,
struct rxrpc_call *call,
struct msghdr *msg, size_t len);
/*
* extract control messages from the sendmsg() control buffer
*/
static int rxrpc_sendmsg_cmsg(struct rxrpc_sock *rx, struct msghdr *msg,
unsigned long *user_call_ID,
enum rxrpc_command *command,
u32 *abort_code,
bool server)
{
struct cmsghdr *cmsg;
int len;
*command = RXRPC_CMD_SEND_DATA;
if (msg->msg_controllen == 0)
return -EINVAL;
for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
if (!CMSG_OK(msg, cmsg))
return -EINVAL;
len = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
_debug("CMSG %d, %d, %d",
cmsg->cmsg_level, cmsg->cmsg_type, len);
if (cmsg->cmsg_level != SOL_RXRPC)
continue;
switch (cmsg->cmsg_type) {
case RXRPC_USER_CALL_ID:
if (msg->msg_flags & MSG_CMSG_COMPAT) {
if (len != sizeof(u32))
return -EINVAL;
*user_call_ID = *(u32 *) CMSG_DATA(cmsg);
} else {
if (len != sizeof(unsigned long))
return -EINVAL;
*user_call_ID = *(unsigned long *)
CMSG_DATA(cmsg);
}
_debug("User Call ID %lx", *user_call_ID);
break;
case RXRPC_ABORT:
if (*command != RXRPC_CMD_SEND_DATA)
return -EINVAL;
*command = RXRPC_CMD_SEND_ABORT;
if (len != sizeof(*abort_code))
return -EINVAL;
*abort_code = *(unsigned int *) CMSG_DATA(cmsg);
_debug("Abort %x", *abort_code);
if (*abort_code == 0)
return -EINVAL;
break;
case RXRPC_ACCEPT:
if (*command != RXRPC_CMD_SEND_DATA)
return -EINVAL;
*command = RXRPC_CMD_ACCEPT;
if (len != 0)
return -EINVAL;
if (!server)
return -EISCONN;
break;
default:
return -EINVAL;
}
}
_leave(" = 0");
return 0;
}
/*
* abort a call, sending an ABORT packet to the peer
*/
static void rxrpc_send_abort(struct rxrpc_call *call, u32 abort_code)
{
write_lock_bh(&call->state_lock);
if (call->state <= RXRPC_CALL_COMPLETE) {
call->state = RXRPC_CALL_LOCALLY_ABORTED;
call->abort_code = abort_code;
set_bit(RXRPC_CALL_ABORT, &call->events);
del_timer_sync(&call->resend_timer);
del_timer_sync(&call->ack_timer);
clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
clear_bit(RXRPC_CALL_ACK, &call->events);
clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
rxrpc_queue_call(call);
}
write_unlock_bh(&call->state_lock);
}
/*
* send a message forming part of a client call through an RxRPC socket
* - caller holds the socket locked
* - the socket may be either a client socket or a server socket
*/
int rxrpc_client_sendmsg(struct kiocb *iocb, struct rxrpc_sock *rx,
struct rxrpc_transport *trans, struct msghdr *msg,
size_t len)
{
struct rxrpc_conn_bundle *bundle;
enum rxrpc_command cmd;
struct rxrpc_call *call;
unsigned long user_call_ID = 0;
struct key *key;
__be16 service_id;
u32 abort_code = 0;
int ret;
_enter("");
ASSERT(trans != NULL);
ret = rxrpc_sendmsg_cmsg(rx, msg, &user_call_ID, &cmd, &abort_code,
false);
if (ret < 0)
return ret;
bundle = NULL;
if (trans) {
service_id = rx->service_id;
if (msg->msg_name) {
struct sockaddr_rxrpc *srx =
(struct sockaddr_rxrpc *) msg->msg_name;
service_id = htons(srx->srx_service);
}
key = rx->key;
if (key && !rx->key->payload.data)
key = NULL;
bundle = rxrpc_get_bundle(rx, trans, key, service_id,
GFP_KERNEL);
if (IS_ERR(bundle))
return PTR_ERR(bundle);
}
call = rxrpc_get_client_call(rx, trans, bundle, user_call_ID,
abort_code == 0, GFP_KERNEL);
if (trans)
rxrpc_put_bundle(trans, bundle);
if (IS_ERR(call)) {
_leave(" = %ld", PTR_ERR(call));
return PTR_ERR(call);
}
_debug("CALL %d USR %lx ST %d on CONN %p",
call->debug_id, call->user_call_ID, call->state, call->conn);
if (call->state >= RXRPC_CALL_COMPLETE) {
/* it's too late for this call */
ret = -ESHUTDOWN;
} else if (cmd == RXRPC_CMD_SEND_ABORT) {
rxrpc_send_abort(call, abort_code);
} else if (cmd != RXRPC_CMD_SEND_DATA) {
ret = -EINVAL;
} else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
/* request phase complete for this client call */
ret = -EPROTO;
} else {
ret = rxrpc_send_data(iocb, rx, call, msg, len);
}
rxrpc_put_call(call);
_leave(" = %d", ret);
return ret;
}
/**
* rxrpc_kernel_send_data - Allow a kernel service to send data on a call
* @call: The call to send data through
* @msg: The data to send
* @len: The amount of data to send
*
* Allow a kernel service to send data on a call. The call must be in an state
* appropriate to sending data. No control data should be supplied in @msg,
* nor should an address be supplied. MSG_MORE should be flagged if there's
* more data to come, otherwise this data will end the transmission phase.
*/
int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
size_t len)
{
int ret;
_enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]);
ASSERTCMP(msg->msg_name, ==, NULL);
ASSERTCMP(msg->msg_control, ==, NULL);
lock_sock(&call->socket->sk);
_debug("CALL %d USR %lx ST %d on CONN %p",
call->debug_id, call->user_call_ID, call->state, call->conn);
if (call->state >= RXRPC_CALL_COMPLETE) {
ret = -ESHUTDOWN; /* it's too late for this call */
} else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
ret = -EPROTO; /* request phase complete for this client call */
} else {
mm_segment_t oldfs = get_fs();
set_fs(KERNEL_DS);
ret = rxrpc_send_data(NULL, call->socket, call, msg, len);
set_fs(oldfs);
}
release_sock(&call->socket->sk);
_leave(" = %d", ret);
return ret;
}
EXPORT_SYMBOL(rxrpc_kernel_send_data);
/*
* rxrpc_kernel_abort_call - Allow a kernel service to abort a call
* @call: The call to be aborted
* @abort_code: The abort code to stick into the ABORT packet
*
* Allow a kernel service to abort a call, if it's still in an abortable state.
*/
void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code)
{
_enter("{%d},%d", call->debug_id, abort_code);
lock_sock(&call->socket->sk);
_debug("CALL %d USR %lx ST %d on CONN %p",
call->debug_id, call->user_call_ID, call->state, call->conn);
if (call->state < RXRPC_CALL_COMPLETE)
rxrpc_send_abort(call, abort_code);
release_sock(&call->socket->sk);
_leave("");
}
EXPORT_SYMBOL(rxrpc_kernel_abort_call);
/*
* send a message through a server socket
* - caller holds the socket locked
*/
int rxrpc_server_sendmsg(struct kiocb *iocb, struct rxrpc_sock *rx,
struct msghdr *msg, size_t len)
{
enum rxrpc_command cmd;
struct rxrpc_call *call;
unsigned long user_call_ID = 0;
u32 abort_code = 0;
int ret;
_enter("");
ret = rxrpc_sendmsg_cmsg(rx, msg, &user_call_ID, &cmd, &abort_code,
true);
if (ret < 0)
return ret;
if (cmd == RXRPC_CMD_ACCEPT) {
call = rxrpc_accept_call(rx, user_call_ID);
if (IS_ERR(call))
return PTR_ERR(call);
rxrpc_put_call(call);
return 0;
}
call = rxrpc_find_server_call(rx, user_call_ID);
if (!call)
return -EBADSLT;
if (call->state >= RXRPC_CALL_COMPLETE) {
ret = -ESHUTDOWN;
goto out;
}
switch (cmd) {
case RXRPC_CMD_SEND_DATA:
if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
/* Tx phase not yet begun for this call */
ret = -EPROTO;
break;
}
ret = rxrpc_send_data(iocb, rx, call, msg, len);
break;
case RXRPC_CMD_SEND_ABORT:
rxrpc_send_abort(call, abort_code);
break;
default:
BUG();
}
out:
rxrpc_put_call(call);
_leave(" = %d", ret);
return ret;
}
/*
* send a packet through the transport endpoint
*/
int rxrpc_send_packet(struct rxrpc_transport *trans, struct sk_buff *skb)
{
struct kvec iov[1];
struct msghdr msg;
int ret, opt;
_enter(",{%d}", skb->len);
iov[0].iov_base = skb->head;
iov[0].iov_len = skb->len;
msg.msg_name = &trans->peer->srx.transport.sin;
msg.msg_namelen = sizeof(trans->peer->srx.transport.sin);
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
/* send the packet with the don't fragment bit set if we currently
* think it's small enough */
if (skb->len - sizeof(struct rxrpc_header) < trans->peer->maxdata) {
down_read(&trans->local->defrag_sem);
/* send the packet by UDP
* - returns -EMSGSIZE if UDP would have to fragment the packet
* to go out of the interface
* - in which case, we'll have processed the ICMP error
* message and update the peer record
*/
ret = kernel_sendmsg(trans->local->socket, &msg, iov, 1,
iov[0].iov_len);
up_read(&trans->local->defrag_sem);
if (ret == -EMSGSIZE)
goto send_fragmentable;
_leave(" = %d [%u]", ret, trans->peer->maxdata);
return ret;
}
send_fragmentable:
/* attempt to send this message with fragmentation enabled */
_debug("send fragment");
down_write(&trans->local->defrag_sem);
opt = IP_PMTUDISC_DONT;
ret = kernel_setsockopt(trans->local->socket, SOL_IP, IP_MTU_DISCOVER,
(char *) &opt, sizeof(opt));
if (ret == 0) {
ret = kernel_sendmsg(trans->local->socket, &msg, iov, 1,
iov[0].iov_len);
opt = IP_PMTUDISC_DO;
kernel_setsockopt(trans->local->socket, SOL_IP,
IP_MTU_DISCOVER, (char *) &opt, sizeof(opt));
}
up_write(&trans->local->defrag_sem);
_leave(" = %d [frag %u]", ret, trans->peer->maxdata);
return ret;
}
/*
* wait for space to appear in the transmit/ACK window
* - caller holds the socket locked
*/
static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
struct rxrpc_call *call,
long *timeo)
{
DECLARE_WAITQUEUE(myself, current);
int ret;
_enter(",{%d},%ld",
CIRC_SPACE(call->acks_head, call->acks_tail, call->acks_winsz),
*timeo);
add_wait_queue(&call->tx_waitq, &myself);
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
ret = 0;
if (CIRC_SPACE(call->acks_head, call->acks_tail,
call->acks_winsz) > 0)
break;
if (signal_pending(current)) {
ret = sock_intr_errno(*timeo);
break;
}
release_sock(&rx->sk);
*timeo = schedule_timeout(*timeo);
lock_sock(&rx->sk);
}
remove_wait_queue(&call->tx_waitq, &myself);
set_current_state(TASK_RUNNING);
_leave(" = %d", ret);
return ret;
}
/*
* attempt to schedule an instant Tx resend
*/
static inline void rxrpc_instant_resend(struct rxrpc_call *call)
{
read_lock_bh(&call->state_lock);
if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
if (call->state < RXRPC_CALL_COMPLETE &&
!test_and_set_bit(RXRPC_CALL_RESEND_TIMER, &call->events))
rxrpc_queue_call(call);
}
read_unlock_bh(&call->state_lock);
}
/*
* queue a packet for transmission, set the resend timer and attempt
* to send the packet immediately
*/
static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
bool last)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
int ret;
_net("queue skb %p [%d]", skb, call->acks_head);
ASSERT(call->acks_window != NULL);
call->acks_window[call->acks_head] = (unsigned long) skb;
smp_wmb();
call->acks_head = (call->acks_head + 1) & (call->acks_winsz - 1);
if (last || call->state == RXRPC_CALL_SERVER_ACK_REQUEST) {
_debug("________awaiting reply/ACK__________");
write_lock_bh(&call->state_lock);
switch (call->state) {
case RXRPC_CALL_CLIENT_SEND_REQUEST:
call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
break;
case RXRPC_CALL_SERVER_ACK_REQUEST:
call->state = RXRPC_CALL_SERVER_SEND_REPLY;
if (!last)
break;
case RXRPC_CALL_SERVER_SEND_REPLY:
call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
break;
default:
break;
}
write_unlock_bh(&call->state_lock);
}
_proto("Tx DATA %%%u { #%u }",
ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));
sp->need_resend = 0;
sp->resend_at = jiffies + rxrpc_resend_timeout * HZ;
if (!test_and_set_bit(RXRPC_CALL_RUN_RTIMER, &call->flags)) {
_debug("run timer");
call->resend_timer.expires = sp->resend_at;
add_timer(&call->resend_timer);
}
/* attempt to cancel the rx-ACK timer, deferring reply transmission if
* we're ACK'ing the request phase of an incoming call */
ret = -EAGAIN;
if (try_to_del_timer_sync(&call->ack_timer) >= 0) {
/* the packet may be freed by rxrpc_process_call() before this
* returns */
ret = rxrpc_send_packet(call->conn->trans, skb);
_net("sent skb %p", skb);
} else {
_debug("failed to delete ACK timer");
}
if (ret < 0) {
_debug("need instant resend %d", ret);
sp->need_resend = 1;
rxrpc_instant_resend(call);
}
_leave("");
}
/*
* send data through a socket
* - must be called in process context
* - caller holds the socket locked
*/
static int rxrpc_send_data(struct kiocb *iocb,
struct rxrpc_sock *rx,
struct rxrpc_call *call,
struct msghdr *msg, size_t len)
{
struct rxrpc_skb_priv *sp;
unsigned char __user *from;
struct sk_buff *skb;
struct iovec *iov;
struct sock *sk = &rx->sk;
long timeo;
bool more;
int ret, ioc, segment, copied;
_enter(",,,{%zu},%zu", msg->msg_iovlen, len);
timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
/* this should be in poll */
clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
return -EPIPE;
iov = msg->msg_iov;
ioc = msg->msg_iovlen - 1;
from = iov->iov_base;
segment = iov->iov_len;
iov++;
more = msg->msg_flags & MSG_MORE;
skb = call->tx_pending;
call->tx_pending = NULL;
copied = 0;
do {
int copy;
if (segment > len)
segment = len;
_debug("SEGMENT %d @%p", segment, from);
if (!skb) {
size_t size, chunk, max, space;
_debug("alloc");
if (CIRC_SPACE(call->acks_head, call->acks_tail,
call->acks_winsz) <= 0) {
ret = -EAGAIN;
if (msg->msg_flags & MSG_DONTWAIT)
goto maybe_error;
ret = rxrpc_wait_for_tx_window(rx, call,
&timeo);
if (ret < 0)
goto maybe_error;
}
max = call->conn->trans->peer->maxdata;
max -= call->conn->security_size;
max &= ~(call->conn->size_align - 1UL);
chunk = max;
if (chunk > len && !more)
chunk = len;
space = chunk + call->conn->size_align;
space &= ~(call->conn->size_align - 1UL);
size = space + call->conn->header_size;
_debug("SIZE: %zu/%zu/%zu", chunk, space, size);
/* create a buffer that we can retain until it's ACK'd */
skb = sock_alloc_send_skb(
sk, size, msg->msg_flags & MSG_DONTWAIT, &ret);
if (!skb)
goto maybe_error;
rxrpc_new_skb(skb);
_debug("ALLOC SEND %p", skb);
ASSERTCMP(skb->mark, ==, 0);
_debug("HS: %u", call->conn->header_size);
skb_reserve(skb, call->conn->header_size);
skb->len += call->conn->header_size;
sp = rxrpc_skb(skb);
sp->remain = chunk;
if (sp->remain > skb_tailroom(skb))
sp->remain = skb_tailroom(skb);
_net("skb: hr %d, tr %d, hl %d, rm %d",
skb_headroom(skb),
skb_tailroom(skb),
skb_headlen(skb),
sp->remain);
skb->ip_summed = CHECKSUM_UNNECESSARY;
}
_debug("append");
sp = rxrpc_skb(skb);
/* append next segment of data to the current buffer */
copy = skb_tailroom(skb);
ASSERTCMP(copy, >, 0);
if (copy > segment)
copy = segment;
if (copy > sp->remain)
copy = sp->remain;
_debug("add");
ret = skb_add_data(skb, from, copy);
_debug("added");
if (ret < 0)
goto efault;
sp->remain -= copy;
skb->mark += copy;
copied += copy;
len -= copy;
segment -= copy;
from += copy;
while (segment == 0 && ioc > 0) {
from = iov->iov_base;
segment = iov->iov_len;
iov++;
ioc--;
}
if (len == 0) {
segment = 0;
ioc = 0;
}
/* check for the far side aborting the call or a network error
* occurring */
if (call->state > RXRPC_CALL_COMPLETE)
goto call_aborted;
/* add the packet to the send queue if it's now full */
if (sp->remain <= 0 || (segment == 0 && !more)) {
struct rxrpc_connection *conn = call->conn;
size_t pad;
/* pad out if we're using security */
if (conn->security) {
pad = conn->security_size + skb->mark;
pad = conn->size_align - pad;
pad &= conn->size_align - 1;
_debug("pad %zu", pad);
if (pad)
memset(skb_put(skb, pad), 0, pad);
}
sp->hdr.epoch = conn->epoch;
sp->hdr.cid = call->cid;
sp->hdr.callNumber = call->call_id;
sp->hdr.seq =
htonl(atomic_inc_return(&call->sequence));
sp->hdr.serial =
htonl(atomic_inc_return(&conn->serial));
sp->hdr.type = RXRPC_PACKET_TYPE_DATA;
sp->hdr.userStatus = 0;
sp->hdr.securityIndex = conn->security_ix;
sp->hdr._rsvd = 0;
sp->hdr.serviceId = conn->service_id;
sp->hdr.flags = conn->out_clientflag;
if (len == 0 && !more)
sp->hdr.flags |= RXRPC_LAST_PACKET;
else if (CIRC_SPACE(call->acks_head, call->acks_tail,
call->acks_winsz) > 1)
sp->hdr.flags |= RXRPC_MORE_PACKETS;
ret = rxrpc_secure_packet(
call, skb, skb->mark,
skb->head + sizeof(struct rxrpc_header));
if (ret < 0)
goto out;
memcpy(skb->head, &sp->hdr,
sizeof(struct rxrpc_header));
rxrpc_queue_packet(call, skb, segment == 0 && !more);
skb = NULL;
}
} while (segment > 0);
success:
ret = copied;
out:
call->tx_pending = skb;
_leave(" = %d", ret);
return ret;
call_aborted:
rxrpc_free_skb(skb);
if (call->state == RXRPC_CALL_NETWORK_ERROR)
ret = call->conn->trans->peer->net_error;
else
ret = -ECONNABORTED;
_leave(" = %d", ret);
return ret;
maybe_error:
if (copied)
goto success;
goto out;
efault:
ret = -EFAULT;
goto out;
}
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