// SPDX-License-Identifier: GPL-2.0-or-later /* RxRPC packet transmission * * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/net.h> #include <linux/gfp.h> #include <linux/skbuff.h> #include <linux/export.h> #include <net/sock.h> #include <net/af_rxrpc.h> #include "ar-internal.h" struct rxrpc_ack_buffer { struct rxrpc_wire_header whdr; struct rxrpc_ackpacket ack; u8 acks[255]; u8 pad[3]; struct rxrpc_ackinfo ackinfo; }; struct rxrpc_abort_buffer { struct rxrpc_wire_header whdr; __be32 abort_code; }; static const char rxrpc_keepalive_string[] = ""; /* * Increase Tx backoff on transmission failure and clear it on success. */ static void rxrpc_tx_backoff(struct rxrpc_call *call, int ret) { if (ret < 0) { u16 tx_backoff = READ_ONCE(call->tx_backoff); if (tx_backoff < HZ) WRITE_ONCE(call->tx_backoff, tx_backoff + 1); } else { WRITE_ONCE(call->tx_backoff, 0); } } /* * Arrange for a keepalive ping a certain time after we last transmitted. This * lets the far side know we're still interested in this call and helps keep * the route through any intervening firewall open. * * Receiving a response to the ping will prevent the ->expect_rx_by timer from * expiring. */ static void rxrpc_set_keepalive(struct rxrpc_call *call) { unsigned long now = jiffies, keepalive_at = call->next_rx_timo / 6; keepalive_at += now; WRITE_ONCE(call->keepalive_at, keepalive_at); rxrpc_reduce_call_timer(call, keepalive_at, now, rxrpc_timer_set_for_keepalive); } /* * Fill out an ACK packet. */ static size_t rxrpc_fill_out_ack(struct rxrpc_connection *conn, struct rxrpc_call *call, struct rxrpc_ack_buffer *pkt, rxrpc_seq_t *_hard_ack, rxrpc_seq_t *_top, u8 reason) { rxrpc_serial_t serial; rxrpc_seq_t hard_ack, top, seq; int ix; u32 mtu, jmax; u8 *ackp = pkt->acks; /* Barrier against rxrpc_input_data(). */ serial = call->ackr_serial; hard_ack = READ_ONCE(call->rx_hard_ack); top = smp_load_acquire(&call->rx_top); *_hard_ack = hard_ack; *_top = top; pkt->ack.bufferSpace = htons(8); pkt->ack.maxSkew = htons(0); pkt->ack.firstPacket = htonl(hard_ack + 1); pkt->ack.previousPacket = htonl(call->ackr_prev_seq); pkt->ack.serial = htonl(serial); pkt->ack.reason = reason; pkt->ack.nAcks = top - hard_ack; if (reason == RXRPC_ACK_PING) pkt->whdr.flags |= RXRPC_REQUEST_ACK; if (after(top, hard_ack)) { seq = hard_ack + 1; do { ix = seq & RXRPC_RXTX_BUFF_MASK; if (call->rxtx_buffer[ix]) *ackp++ = RXRPC_ACK_TYPE_ACK; else *ackp++ = RXRPC_ACK_TYPE_NACK; seq++; } while (before_eq(seq, top)); } mtu = conn->params.peer->if_mtu; mtu -= conn->params.peer->hdrsize; jmax = (call->nr_jumbo_bad > 3) ? 1 : rxrpc_rx_jumbo_max; pkt->ackinfo.rxMTU = htonl(rxrpc_rx_mtu); pkt->ackinfo.maxMTU = htonl(mtu); pkt->ackinfo.rwind = htonl(call->rx_winsize); pkt->ackinfo.jumbo_max = htonl(jmax); *ackp++ = 0; *ackp++ = 0; *ackp++ = 0; return top - hard_ack + 3; } /* * Record the beginning of an RTT probe. */ static int rxrpc_begin_rtt_probe(struct rxrpc_call *call, rxrpc_serial_t serial, enum rxrpc_rtt_tx_trace why) { unsigned long avail = call->rtt_avail; int rtt_slot = 9; if (!(avail & RXRPC_CALL_RTT_AVAIL_MASK)) goto no_slot; rtt_slot = __ffs(avail & RXRPC_CALL_RTT_AVAIL_MASK); if (!test_and_clear_bit(rtt_slot, &call->rtt_avail)) goto no_slot; call->rtt_serial[rtt_slot] = serial; call->rtt_sent_at[rtt_slot] = ktime_get_real(); smp_wmb(); /* Write data before avail bit */ set_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail); trace_rxrpc_rtt_tx(call, why, rtt_slot, serial); return rtt_slot; no_slot: trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_no_slot, rtt_slot, serial); return -1; } /* * Cancel an RTT probe. */ static void rxrpc_cancel_rtt_probe(struct rxrpc_call *call, rxrpc_serial_t serial, int rtt_slot) { if (rtt_slot != -1) { clear_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail); smp_wmb(); /* Clear pending bit before setting slot */ set_bit(rtt_slot, &call->rtt_avail); trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_cancel, rtt_slot, serial); } } /* * Send an ACK call packet. */ int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping, rxrpc_serial_t *_serial) { struct rxrpc_connection *conn; struct rxrpc_ack_buffer *pkt; struct msghdr msg; struct kvec iov[2]; rxrpc_serial_t serial; rxrpc_seq_t hard_ack, top; size_t len, n; int ret, rtt_slot = -1; u8 reason; if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags)) return -ECONNRESET; pkt = kzalloc(sizeof(*pkt), GFP_KERNEL); if (!pkt) return -ENOMEM; conn = call->conn; msg.msg_name = &call->peer->srx.transport; msg.msg_namelen = call->peer->srx.transport_len; msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_flags = 0; pkt->whdr.epoch = htonl(conn->proto.epoch); pkt->whdr.cid = htonl(call->cid); pkt->whdr.callNumber = htonl(call->call_id); pkt->whdr.seq = 0; pkt->whdr.type = RXRPC_PACKET_TYPE_ACK; pkt->whdr.flags = RXRPC_SLOW_START_OK | conn->out_clientflag; pkt->whdr.userStatus = 0; pkt->whdr.securityIndex = call->security_ix; pkt->whdr._rsvd = 0; pkt->whdr.serviceId = htons(call->service_id); spin_lock_bh(&call->lock); if (ping) { reason = RXRPC_ACK_PING; } else { reason = call->ackr_reason; if (!call->ackr_reason) { spin_unlock_bh(&call->lock); ret = 0; goto out; } call->ackr_reason = 0; } n = rxrpc_fill_out_ack(conn, call, pkt, &hard_ack, &top, reason); spin_unlock_bh(&call->lock); iov[0].iov_base = pkt; iov[0].iov_len = sizeof(pkt->whdr) + sizeof(pkt->ack) + n; iov[1].iov_base = &pkt->ackinfo; iov[1].iov_len = sizeof(pkt->ackinfo); len = iov[0].iov_len + iov[1].iov_len; serial = atomic_inc_return(&conn->serial); pkt->whdr.serial = htonl(serial); trace_rxrpc_tx_ack(call->debug_id, serial, ntohl(pkt->ack.firstPacket), ntohl(pkt->ack.serial), pkt->ack.reason, pkt->ack.nAcks); if (_serial) *_serial = serial; if (ping) rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_ping); ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len); conn->params.peer->last_tx_at = ktime_get_seconds(); if (ret < 0) trace_rxrpc_tx_fail(call->debug_id, serial, ret, rxrpc_tx_point_call_ack); else trace_rxrpc_tx_packet(call->debug_id, &pkt->whdr, rxrpc_tx_point_call_ack); rxrpc_tx_backoff(call, ret); if (call->state < RXRPC_CALL_COMPLETE) { if (ret < 0) { rxrpc_cancel_rtt_probe(call, serial, rtt_slot); rxrpc_propose_ACK(call, pkt->ack.reason, ntohl(pkt->ack.serial), false, true, rxrpc_propose_ack_retry_tx); } else { spin_lock_bh(&call->lock); if (after(hard_ack, call->ackr_consumed)) call->ackr_consumed = hard_ack; if (after(top, call->ackr_seen)) call->ackr_seen = top; spin_unlock_bh(&call->lock); } rxrpc_set_keepalive(call); } out: kfree(pkt); return ret; } /* * Send an ABORT call packet. */ int rxrpc_send_abort_packet(struct rxrpc_call *call) { struct rxrpc_connection *conn; struct rxrpc_abort_buffer pkt; struct msghdr msg; struct kvec iov[1]; rxrpc_serial_t serial; int ret; /* Don't bother sending aborts for a client call once the server has * hard-ACK'd all of its request data. After that point, we're not * going to stop the operation proceeding, and whilst we might limit * the reply, it's not worth it if we can send a new call on the same * channel instead, thereby closing off this call. */ if (rxrpc_is_client_call(call) && test_bit(RXRPC_CALL_TX_LAST, &call->flags)) return 0; if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags)) return -ECONNRESET; conn = call->conn; msg.msg_name = &call->peer->srx.transport; msg.msg_namelen = call->peer->srx.transport_len; msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_flags = 0; pkt.whdr.epoch = htonl(conn->proto.epoch); pkt.whdr.cid = htonl(call->cid); pkt.whdr.callNumber = htonl(call->call_id); pkt.whdr.seq = 0; pkt.whdr.type = RXRPC_PACKET_TYPE_ABORT; pkt.whdr.flags = conn->out_clientflag; pkt.whdr.userStatus = 0; pkt.whdr.securityIndex = call->security_ix; pkt.whdr._rsvd = 0; pkt.whdr.serviceId = htons(call->service_id); pkt.abort_code = htonl(call->abort_code); iov[0].iov_base = &pkt; iov[0].iov_len = sizeof(pkt); serial = atomic_inc_return(&conn->serial); pkt.whdr.serial = htonl(serial); ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 1, sizeof(pkt)); conn->params.peer->last_tx_at = ktime_get_seconds(); if (ret < 0) trace_rxrpc_tx_fail(call->debug_id, serial, ret, rxrpc_tx_point_call_abort); else trace_rxrpc_tx_packet(call->debug_id, &pkt.whdr, rxrpc_tx_point_call_abort); rxrpc_tx_backoff(call, ret); return ret; } /* * send a packet through the transport endpoint */ int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb, bool retrans) { struct rxrpc_connection *conn = call->conn; struct rxrpc_wire_header whdr; struct rxrpc_skb_priv *sp = rxrpc_skb(skb); struct msghdr msg; struct kvec iov[2]; rxrpc_serial_t serial; size_t len; int ret, rtt_slot = -1; _enter(",{%d}", skb->len); if (hlist_unhashed(&call->error_link)) { spin_lock_bh(&call->peer->lock); hlist_add_head_rcu(&call->error_link, &call->peer->error_targets); spin_unlock_bh(&call->peer->lock); } /* Each transmission of a Tx packet needs a new serial number */ serial = atomic_inc_return(&conn->serial); whdr.epoch = htonl(conn->proto.epoch); whdr.cid = htonl(call->cid); whdr.callNumber = htonl(call->call_id); whdr.seq = htonl(sp->hdr.seq); whdr.serial = htonl(serial); whdr.type = RXRPC_PACKET_TYPE_DATA; whdr.flags = sp->hdr.flags; whdr.userStatus = 0; whdr.securityIndex = call->security_ix; whdr._rsvd = htons(sp->hdr._rsvd); whdr.serviceId = htons(call->service_id); if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags) && sp->hdr.seq == 1) whdr.userStatus = RXRPC_USERSTATUS_SERVICE_UPGRADE; iov[0].iov_base = &whdr; iov[0].iov_len = sizeof(whdr); iov[1].iov_base = skb->head; iov[1].iov_len = skb->len; len = iov[0].iov_len + iov[1].iov_len; msg.msg_name = &call->peer->srx.transport; msg.msg_namelen = call->peer->srx.transport_len; msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_flags = 0; /* If our RTT cache needs working on, request an ACK. Also request * ACKs if a DATA packet appears to have been lost. * * However, we mustn't request an ACK on the last reply packet of a * service call, lest OpenAFS incorrectly send us an ACK with some * soft-ACKs in it and then never follow up with a proper hard ACK. */ if ((!(sp->hdr.flags & RXRPC_LAST_PACKET) || rxrpc_to_server(sp) ) && (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events) || retrans || call->cong_mode == RXRPC_CALL_SLOW_START || (call->peer->rtt_count < 3 && sp->hdr.seq & 1) || ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), ktime_get_real()))) whdr.flags |= RXRPC_REQUEST_ACK; if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) { static int lose; if ((lose++ & 7) == 7) { ret = 0; trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags, retrans, true); goto done; } } trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags, retrans, false); /* send the packet with the don't fragment bit set if we currently * think it's small enough */ if (iov[1].iov_len >= call->peer->maxdata) goto send_fragmentable; down_read(&conn->params.local->defrag_sem); sp->hdr.serial = serial; smp_wmb(); /* Set serial before timestamp */ skb->tstamp = ktime_get_real(); if (whdr.flags & RXRPC_REQUEST_ACK) rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_data); /* 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(conn->params.local->socket, &msg, iov, 2, len); conn->params.peer->last_tx_at = ktime_get_seconds(); up_read(&conn->params.local->defrag_sem); if (ret < 0) { rxrpc_cancel_rtt_probe(call, serial, rtt_slot); trace_rxrpc_tx_fail(call->debug_id, serial, ret, rxrpc_tx_point_call_data_nofrag); } else { trace_rxrpc_tx_packet(call->debug_id, &whdr, rxrpc_tx_point_call_data_nofrag); } rxrpc_tx_backoff(call, ret); if (ret == -EMSGSIZE) goto send_fragmentable; done: if (ret >= 0) { if (whdr.flags & RXRPC_REQUEST_ACK) { call->peer->rtt_last_req = skb->tstamp; if (call->peer->rtt_count > 1) { unsigned long nowj = jiffies, ack_lost_at; ack_lost_at = rxrpc_get_rto_backoff(call->peer, retrans); ack_lost_at += nowj; WRITE_ONCE(call->ack_lost_at, ack_lost_at); rxrpc_reduce_call_timer(call, ack_lost_at, nowj, rxrpc_timer_set_for_lost_ack); } } if (sp->hdr.seq == 1 && !test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER, &call->flags)) { unsigned long nowj = jiffies, expect_rx_by; expect_rx_by = nowj + call->next_rx_timo; WRITE_ONCE(call->expect_rx_by, expect_rx_by); rxrpc_reduce_call_timer(call, expect_rx_by, nowj, rxrpc_timer_set_for_normal); } rxrpc_set_keepalive(call); } else { /* Cancel the call if the initial transmission fails, * particularly if that's due to network routing issues that * aren't going away anytime soon. The layer above can arrange * the retransmission. */ if (!test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER, &call->flags)) rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR, RX_USER_ABORT, ret); } _leave(" = %d [%u]", ret, call->peer->maxdata); return ret; send_fragmentable: /* attempt to send this message with fragmentation enabled */ _debug("send fragment"); down_write(&conn->params.local->defrag_sem); sp->hdr.serial = serial; smp_wmb(); /* Set serial before timestamp */ skb->tstamp = ktime_get_real(); if (whdr.flags & RXRPC_REQUEST_ACK) rtt_slot = rxrpc_begin_rtt_probe(call, serial, rxrpc_rtt_tx_data); switch (conn->params.local->srx.transport.family) { case AF_INET6: case AF_INET: ip_sock_set_mtu_discover(conn->params.local->socket->sk, IP_PMTUDISC_DONT); ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len); conn->params.peer->last_tx_at = ktime_get_seconds(); ip_sock_set_mtu_discover(conn->params.local->socket->sk, IP_PMTUDISC_DO); break; default: BUG(); } if (ret < 0) { rxrpc_cancel_rtt_probe(call, serial, rtt_slot); trace_rxrpc_tx_fail(call->debug_id, serial, ret, rxrpc_tx_point_call_data_frag); } else { trace_rxrpc_tx_packet(call->debug_id, &whdr, rxrpc_tx_point_call_data_frag); } rxrpc_tx_backoff(call, ret); up_write(&conn->params.local->defrag_sem); goto done; } /* * reject packets through the local endpoint */ void rxrpc_reject_packets(struct rxrpc_local *local) { struct sockaddr_rxrpc srx; struct rxrpc_skb_priv *sp; struct rxrpc_wire_header whdr; struct sk_buff *skb; struct msghdr msg; struct kvec iov[2]; size_t size; __be32 code; int ret, ioc; _enter("%d", local->debug_id); iov[0].iov_base = &whdr; iov[0].iov_len = sizeof(whdr); iov[1].iov_base = &code; iov[1].iov_len = sizeof(code); msg.msg_name = &srx.transport; msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_flags = 0; memset(&whdr, 0, sizeof(whdr)); while ((skb = skb_dequeue(&local->reject_queue))) { rxrpc_see_skb(skb, rxrpc_skb_seen); sp = rxrpc_skb(skb); switch (skb->mark) { case RXRPC_SKB_MARK_REJECT_BUSY: whdr.type = RXRPC_PACKET_TYPE_BUSY; size = sizeof(whdr); ioc = 1; break; case RXRPC_SKB_MARK_REJECT_ABORT: whdr.type = RXRPC_PACKET_TYPE_ABORT; code = htonl(skb->priority); size = sizeof(whdr) + sizeof(code); ioc = 2; break; default: rxrpc_free_skb(skb, rxrpc_skb_freed); continue; } if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) { msg.msg_namelen = srx.transport_len; whdr.epoch = htonl(sp->hdr.epoch); whdr.cid = htonl(sp->hdr.cid); whdr.callNumber = htonl(sp->hdr.callNumber); whdr.serviceId = htons(sp->hdr.serviceId); whdr.flags = sp->hdr.flags; whdr.flags ^= RXRPC_CLIENT_INITIATED; whdr.flags &= RXRPC_CLIENT_INITIATED; ret = kernel_sendmsg(local->socket, &msg, iov, ioc, size); if (ret < 0) trace_rxrpc_tx_fail(local->debug_id, 0, ret, rxrpc_tx_point_reject); else trace_rxrpc_tx_packet(local->debug_id, &whdr, rxrpc_tx_point_reject); } rxrpc_free_skb(skb, rxrpc_skb_freed); } _leave(""); } /* * Send a VERSION reply to a peer as a keepalive. */ void rxrpc_send_keepalive(struct rxrpc_peer *peer) { struct rxrpc_wire_header whdr; struct msghdr msg; struct kvec iov[2]; size_t len; int ret; _enter(""); msg.msg_name = &peer->srx.transport; msg.msg_namelen = peer->srx.transport_len; msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_flags = 0; whdr.epoch = htonl(peer->local->rxnet->epoch); whdr.cid = 0; whdr.callNumber = 0; whdr.seq = 0; whdr.serial = 0; whdr.type = RXRPC_PACKET_TYPE_VERSION; /* Not client-initiated */ whdr.flags = RXRPC_LAST_PACKET; whdr.userStatus = 0; whdr.securityIndex = 0; whdr._rsvd = 0; whdr.serviceId = 0; iov[0].iov_base = &whdr; iov[0].iov_len = sizeof(whdr); iov[1].iov_base = (char *)rxrpc_keepalive_string; iov[1].iov_len = sizeof(rxrpc_keepalive_string); len = iov[0].iov_len + iov[1].iov_len; _proto("Tx VERSION (keepalive)"); ret = kernel_sendmsg(peer->local->socket, &msg, iov, 2, len); if (ret < 0) trace_rxrpc_tx_fail(peer->debug_id, 0, ret, rxrpc_tx_point_version_keepalive); else trace_rxrpc_tx_packet(peer->debug_id, &whdr, rxrpc_tx_point_version_keepalive); peer->last_tx_at = ktime_get_seconds(); _leave(""); }