/* RxRPC recvmsg() implementation * * 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. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include "ar-internal.h" /* * Post a call for attention by the socket or kernel service. Further * notifications are suppressed by putting recvmsg_link on a dummy queue. */ void rxrpc_notify_socket(struct rxrpc_call *call) { struct rxrpc_sock *rx; struct sock *sk; _enter("%d", call->debug_id); if (!list_empty(&call->recvmsg_link)) return; rcu_read_lock(); rx = rcu_dereference(call->socket); sk = &rx->sk; if (rx && sk->sk_state < RXRPC_CLOSE) { if (call->notify_rx) { call->notify_rx(sk, call, call->user_call_ID); } else { write_lock_bh(&rx->recvmsg_lock); if (list_empty(&call->recvmsg_link)) { rxrpc_get_call(call, rxrpc_call_got); list_add_tail(&call->recvmsg_link, &rx->recvmsg_q); } write_unlock_bh(&rx->recvmsg_lock); if (!sock_flag(sk, SOCK_DEAD)) { _debug("call %ps", sk->sk_data_ready); sk->sk_data_ready(sk); } } } rcu_read_unlock(); _leave(""); } /* * Pass a call terminating message to userspace. */ static int rxrpc_recvmsg_term(struct rxrpc_call *call, struct msghdr *msg) { u32 tmp = 0; int ret; switch (call->completion) { case RXRPC_CALL_SUCCEEDED: ret = 0; if (rxrpc_is_service_call(call)) ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ACK, 0, &tmp); break; case RXRPC_CALL_REMOTELY_ABORTED: tmp = call->abort_code; ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &tmp); break; case RXRPC_CALL_LOCALLY_ABORTED: tmp = call->abort_code; ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &tmp); break; case RXRPC_CALL_NETWORK_ERROR: tmp = call->error; ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NET_ERROR, 4, &tmp); break; case RXRPC_CALL_LOCAL_ERROR: tmp = call->error; ret = put_cmsg(msg, SOL_RXRPC, RXRPC_LOCAL_ERROR, 4, &tmp); break; default: pr_err("Invalid terminal call state %u\n", call->state); BUG(); break; } trace_rxrpc_recvmsg(call, rxrpc_recvmsg_terminal, call->rx_hard_ack, call->rx_pkt_offset, call->rx_pkt_len, ret); return ret; } /* * Pass back notification of a new call. The call is added to the * to-be-accepted list. This means that the next call to be accepted might not * be the last call seen awaiting acceptance, but unless we leave this on the * front of the queue and block all other messages until someone gives us a * user_ID for it, there's not a lot we can do. */ static int rxrpc_recvmsg_new_call(struct rxrpc_sock *rx, struct rxrpc_call *call, struct msghdr *msg, int flags) { int tmp = 0, ret; ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NEW_CALL, 0, &tmp); if (ret == 0 && !(flags & MSG_PEEK)) { _debug("to be accepted"); write_lock_bh(&rx->recvmsg_lock); list_del_init(&call->recvmsg_link); write_unlock_bh(&rx->recvmsg_lock); rxrpc_get_call(call, rxrpc_call_got); write_lock(&rx->call_lock); list_add_tail(&call->accept_link, &rx->to_be_accepted); write_unlock(&rx->call_lock); } trace_rxrpc_recvmsg(call, rxrpc_recvmsg_to_be_accepted, 1, 0, 0, ret); return ret; } /* * End the packet reception phase. */ static void rxrpc_end_rx_phase(struct rxrpc_call *call) { _enter("%d,%s", call->debug_id, rxrpc_call_states[call->state]); trace_rxrpc_receive(call, rxrpc_receive_end, 0, call->rx_top); ASSERTCMP(call->rx_hard_ack, ==, call->rx_top); if (call->state == RXRPC_CALL_CLIENT_RECV_REPLY) { rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, 0, 0, true, false); rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK); } else { rxrpc_propose_ACK(call, RXRPC_ACK_IDLE, 0, 0, false, false); } write_lock_bh(&call->state_lock); switch (call->state) { case RXRPC_CALL_CLIENT_RECV_REPLY: __rxrpc_call_completed(call); break; case RXRPC_CALL_SERVER_RECV_REQUEST: call->state = RXRPC_CALL_SERVER_ACK_REQUEST; break; default: break; } write_unlock_bh(&call->state_lock); } /* * Discard a packet we've used up and advance the Rx window by one. */ static void rxrpc_rotate_rx_window(struct rxrpc_call *call) { struct rxrpc_skb_priv *sp; struct sk_buff *skb; rxrpc_serial_t serial; rxrpc_seq_t hard_ack, top; u8 flags; int ix; _enter("%d", call->debug_id); hard_ack = call->rx_hard_ack; top = smp_load_acquire(&call->rx_top); ASSERT(before(hard_ack, top)); hard_ack++; ix = hard_ack & RXRPC_RXTX_BUFF_MASK; skb = call->rxtx_buffer[ix]; rxrpc_see_skb(skb); sp = rxrpc_skb(skb); flags = sp->hdr.flags; serial = sp->hdr.serial; if (call->rxtx_annotations[ix] & RXRPC_RX_ANNO_JUMBO) serial += (call->rxtx_annotations[ix] & RXRPC_RX_ANNO_JUMBO) - 1; call->rxtx_buffer[ix] = NULL; call->rxtx_annotations[ix] = 0; /* Barrier against rxrpc_input_data(). */ smp_store_release(&call->rx_hard_ack, hard_ack); rxrpc_free_skb(skb); _debug("%u,%u,%02x", hard_ack, top, flags); trace_rxrpc_receive(call, rxrpc_receive_rotate, serial, hard_ack); if (flags & RXRPC_LAST_PACKET) rxrpc_end_rx_phase(call); } /* * Decrypt and verify a (sub)packet. The packet's length may be changed due to * padding, but if this is the case, the packet length will be resident in the * socket buffer. Note that we can't modify the master skb info as the skb may * be the home to multiple subpackets. */ static int rxrpc_verify_packet(struct rxrpc_call *call, struct sk_buff *skb, u8 annotation, unsigned int offset, unsigned int len) { struct rxrpc_skb_priv *sp = rxrpc_skb(skb); rxrpc_seq_t seq = sp->hdr.seq; u16 cksum = sp->hdr.cksum; _enter(""); /* For all but the head jumbo subpacket, the security checksum is in a * jumbo header immediately prior to the data. */ if ((annotation & RXRPC_RX_ANNO_JUMBO) > 1) { __be16 tmp; if (skb_copy_bits(skb, offset - 2, &tmp, 2) < 0) BUG(); cksum = ntohs(tmp); seq += (annotation & RXRPC_RX_ANNO_JUMBO) - 1; } return call->conn->security->verify_packet(call, skb, offset, len, seq, cksum); } /* * Locate the data within a packet. This is complicated by: * * (1) An skb may contain a jumbo packet - so we have to find the appropriate * subpacket. * * (2) The (sub)packets may be encrypted and, if so, the encrypted portion * contains an extra header which includes the true length of the data, * excluding any encrypted padding. */ static int rxrpc_locate_data(struct rxrpc_call *call, struct sk_buff *skb, u8 *_annotation, unsigned int *_offset, unsigned int *_len) { struct rxrpc_skb_priv *sp = rxrpc_skb(skb); unsigned int offset = *_offset; unsigned int len = *_len; int ret; u8 annotation = *_annotation; /* Locate the subpacket */ offset = sp->offset; len = skb->len - sp->offset; if ((annotation & RXRPC_RX_ANNO_JUMBO) > 0) { offset += (((annotation & RXRPC_RX_ANNO_JUMBO) - 1) * RXRPC_JUMBO_SUBPKTLEN); len = (annotation & RXRPC_RX_ANNO_JLAST) ? skb->len - offset : RXRPC_JUMBO_SUBPKTLEN; } if (!(annotation & RXRPC_RX_ANNO_VERIFIED)) { ret = rxrpc_verify_packet(call, skb, annotation, offset, len); if (ret < 0) return ret; *_annotation |= RXRPC_RX_ANNO_VERIFIED; } *_offset = offset; *_len = len; call->conn->security->locate_data(call, skb, _offset, _len); return 0; } /* * Deliver messages to a call. This keeps processing packets until the buffer * is filled and we find either more DATA (returns 0) or the end of the DATA * (returns 1). If more packets are required, it returns -EAGAIN. */ static int rxrpc_recvmsg_data(struct socket *sock, struct rxrpc_call *call, struct msghdr *msg, struct iov_iter *iter, size_t len, int flags, size_t *_offset) { struct rxrpc_skb_priv *sp; struct sk_buff *skb; rxrpc_seq_t hard_ack, top, seq; size_t remain; bool last; unsigned int rx_pkt_offset, rx_pkt_len; int ix, copy, ret = -EAGAIN, ret2; rx_pkt_offset = call->rx_pkt_offset; rx_pkt_len = call->rx_pkt_len; if (call->state >= RXRPC_CALL_SERVER_ACK_REQUEST) { seq = call->rx_hard_ack; ret = 1; goto done; } /* Barriers against rxrpc_input_data(). */ hard_ack = call->rx_hard_ack; top = smp_load_acquire(&call->rx_top); for (seq = hard_ack + 1; before_eq(seq, top); seq++) { ix = seq & RXRPC_RXTX_BUFF_MASK; skb = call->rxtx_buffer[ix]; if (!skb) { trace_rxrpc_recvmsg(call, rxrpc_recvmsg_hole, seq, rx_pkt_offset, rx_pkt_len, 0); break; } smp_rmb(); rxrpc_see_skb(skb); sp = rxrpc_skb(skb); if (!(flags & MSG_PEEK)) trace_rxrpc_receive(call, rxrpc_receive_front, sp->hdr.serial, seq); if (msg) sock_recv_timestamp(msg, sock->sk, skb); if (rx_pkt_offset == 0) { ret2 = rxrpc_locate_data(call, skb, &call->rxtx_annotations[ix], &rx_pkt_offset, &rx_pkt_len); trace_rxrpc_recvmsg(call, rxrpc_recvmsg_next, seq, rx_pkt_offset, rx_pkt_len, ret2); if (ret2 < 0) { ret = ret2; goto out; } } else { trace_rxrpc_recvmsg(call, rxrpc_recvmsg_cont, seq, rx_pkt_offset, rx_pkt_len, 0); } /* We have to handle short, empty and used-up DATA packets. */ remain = len - *_offset; copy = rx_pkt_len; if (copy > remain) copy = remain; if (copy > 0) { ret2 = skb_copy_datagram_iter(skb, rx_pkt_offset, iter, copy); if (ret2 < 0) { ret = ret2; goto out; } /* handle piecemeal consumption of data packets */ rx_pkt_offset += copy; rx_pkt_len -= copy; *_offset += copy; } if (rx_pkt_len > 0) { trace_rxrpc_recvmsg(call, rxrpc_recvmsg_full, seq, rx_pkt_offset, rx_pkt_len, 0); ASSERTCMP(*_offset, ==, len); ret = 0; break; } /* The whole packet has been transferred. */ last = sp->hdr.flags & RXRPC_LAST_PACKET; if (!(flags & MSG_PEEK)) rxrpc_rotate_rx_window(call); rx_pkt_offset = 0; rx_pkt_len = 0; if (last) { ASSERTCMP(seq, ==, READ_ONCE(call->rx_top)); ret = 1; goto out; } } out: if (!(flags & MSG_PEEK)) { call->rx_pkt_offset = rx_pkt_offset; call->rx_pkt_len = rx_pkt_len; } done: trace_rxrpc_recvmsg(call, rxrpc_recvmsg_data_return, seq, rx_pkt_offset, rx_pkt_len, ret); return ret; } /* * Receive a message from an RxRPC socket * - we need to be careful about two or more threads calling recvmsg * simultaneously */ int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, int flags) { struct rxrpc_call *call; struct rxrpc_sock *rx = rxrpc_sk(sock->sk); struct list_head *l; size_t copied = 0; long timeo; int ret; DEFINE_WAIT(wait); trace_rxrpc_recvmsg(NULL, rxrpc_recvmsg_enter, 0, 0, 0, 0); if (flags & (MSG_OOB | MSG_TRUNC)) return -EOPNOTSUPP; timeo = sock_rcvtimeo(&rx->sk, flags & MSG_DONTWAIT); try_again: lock_sock(&rx->sk); /* Return immediately if a client socket has no outstanding calls */ if (RB_EMPTY_ROOT(&rx->calls) && list_empty(&rx->recvmsg_q) && rx->sk.sk_state != RXRPC_SERVER_LISTENING) { release_sock(&rx->sk); return -ENODATA; } if (list_empty(&rx->recvmsg_q)) { ret = -EWOULDBLOCK; if (timeo == 0) { call = NULL; goto error_no_call; } release_sock(&rx->sk); /* Wait for something to happen */ prepare_to_wait_exclusive(sk_sleep(&rx->sk), &wait, TASK_INTERRUPTIBLE); ret = sock_error(&rx->sk); if (ret) goto wait_error; if (list_empty(&rx->recvmsg_q)) { if (signal_pending(current)) goto wait_interrupted; trace_rxrpc_recvmsg(NULL, rxrpc_recvmsg_wait, 0, 0, 0, 0); timeo = schedule_timeout(timeo); } finish_wait(sk_sleep(&rx->sk), &wait); goto try_again; } /* Find the next call and dequeue it if we're not just peeking. If we * do dequeue it, that comes with a ref that we will need to release. */ write_lock_bh(&rx->recvmsg_lock); l = rx->recvmsg_q.next; call = list_entry(l, struct rxrpc_call, recvmsg_link); if (!(flags & MSG_PEEK)) list_del_init(&call->recvmsg_link); else rxrpc_get_call(call, rxrpc_call_got); write_unlock_bh(&rx->recvmsg_lock); trace_rxrpc_recvmsg(call, rxrpc_recvmsg_dequeue, 0, 0, 0, 0); if (test_bit(RXRPC_CALL_RELEASED, &call->flags)) BUG(); if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) { if (flags & MSG_CMSG_COMPAT) { unsigned int id32 = call->user_call_ID; ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID, sizeof(unsigned int), &id32); } else { ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID, sizeof(unsigned long), &call->user_call_ID); } if (ret < 0) goto error; } if (msg->msg_name) { size_t len = sizeof(call->conn->params.peer->srx); memcpy(msg->msg_name, &call->conn->params.peer->srx, len); msg->msg_namelen = len; } switch (call->state) { case RXRPC_CALL_SERVER_ACCEPTING: ret = rxrpc_recvmsg_new_call(rx, call, msg, flags); break; case RXRPC_CALL_CLIENT_RECV_REPLY: case RXRPC_CALL_SERVER_RECV_REQUEST: case RXRPC_CALL_SERVER_ACK_REQUEST: ret = rxrpc_recvmsg_data(sock, call, msg, &msg->msg_iter, len, flags, &copied); if (ret == -EAGAIN) ret = 0; if (after(call->rx_top, call->rx_hard_ack) && call->rxtx_buffer[(call->rx_hard_ack + 1) & RXRPC_RXTX_BUFF_MASK]) rxrpc_notify_socket(call); break; default: ret = 0; break; } if (ret < 0) goto error; if (call->state == RXRPC_CALL_COMPLETE) { ret = rxrpc_recvmsg_term(call, msg); if (ret < 0) goto error; if (!(flags & MSG_PEEK)) rxrpc_release_call(rx, call); msg->msg_flags |= MSG_EOR; ret = 1; } if (ret == 0) msg->msg_flags |= MSG_MORE; else msg->msg_flags &= ~MSG_MORE; ret = copied; error: rxrpc_put_call(call, rxrpc_call_put); error_no_call: release_sock(&rx->sk); trace_rxrpc_recvmsg(call, rxrpc_recvmsg_return, 0, 0, 0, ret); return ret; wait_interrupted: ret = sock_intr_errno(timeo); wait_error: finish_wait(sk_sleep(&rx->sk), &wait); call = NULL; goto error_no_call; } /** * rxrpc_kernel_recv_data - Allow a kernel service to receive data/info * @sock: The socket that the call exists on * @call: The call to send data through * @buf: The buffer to receive into * @size: The size of the buffer, including data already read * @_offset: The running offset into the buffer. * @want_more: True if more data is expected to be read * @_abort: Where the abort code is stored if -ECONNABORTED is returned * * Allow a kernel service to receive data and pick up information about the * state of a call. Returns 0 if got what was asked for and there's more * available, 1 if we got what was asked for and we're at the end of the data * and -EAGAIN if we need more data. * * Note that we may return -EAGAIN to drain empty packets at the end of the * data, even if we've already copied over the requested data. * * This function adds the amount it transfers to *_offset, so this should be * precleared as appropriate. Note that the amount remaining in the buffer is * taken to be size - *_offset. * * *_abort should also be initialised to 0. */ int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call, void *buf, size_t size, size_t *_offset, bool want_more, u32 *_abort) { struct iov_iter iter; struct kvec iov; int ret; _enter("{%d,%s},%zu/%zu,%d", call->debug_id, rxrpc_call_states[call->state], *_offset, size, want_more); ASSERTCMP(*_offset, <=, size); ASSERTCMP(call->state, !=, RXRPC_CALL_SERVER_ACCEPTING); iov.iov_base = buf + *_offset; iov.iov_len = size - *_offset; iov_iter_kvec(&iter, ITER_KVEC | READ, &iov, 1, size - *_offset); lock_sock(sock->sk); switch (call->state) { case RXRPC_CALL_CLIENT_RECV_REPLY: case RXRPC_CALL_SERVER_RECV_REQUEST: case RXRPC_CALL_SERVER_ACK_REQUEST: ret = rxrpc_recvmsg_data(sock, call, NULL, &iter, size, 0, _offset); if (ret < 0) goto out; /* We can only reach here with a partially full buffer if we * have reached the end of the data. We must otherwise have a * full buffer or have been given -EAGAIN. */ if (ret == 1) { if (*_offset < size) goto short_data; if (!want_more) goto read_phase_complete; ret = 0; goto out; } if (!want_more) goto excess_data; goto out; case RXRPC_CALL_COMPLETE: goto call_complete; default: ret = -EINPROGRESS; goto out; } read_phase_complete: ret = 1; out: release_sock(sock->sk); _leave(" = %d [%zu,%d]", ret, *_offset, *_abort); return ret; short_data: ret = -EBADMSG; goto out; excess_data: ret = -EMSGSIZE; goto out; call_complete: *_abort = call->abort_code; ret = call->error; if (call->completion == RXRPC_CALL_SUCCEEDED) { ret = 1; if (size > 0) ret = -ECONNRESET; } goto out; } EXPORT_SYMBOL(rxrpc_kernel_recv_data);