diff options
Diffstat (limited to '')
| -rw-r--r-- | net/rxrpc/output.c | 642 |
1 files changed, 642 insertions, 0 deletions
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c new file mode 100644 index 000000000..da8a555ec --- /dev/null +++ b/net/rxrpc/output.c @@ -0,0 +1,642 @@ +/* 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. + */ + +#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(call->ackr_skew); + 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; +} + +/* + * 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; + 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) { + call->ping_serial = serial; + smp_wmb(); + /* We need to stick a time in before we send the packet in case + * the reply gets back before kernel_sendmsg() completes - but + * asking UDP to send the packet can take a relatively long + * time. + */ + call->ping_time = ktime_get_real(); + set_bit(RXRPC_CALL_PINGING, &call->flags); + trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_ping, serial); + } + + 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) { + if (ping) + clear_bit(RXRPC_CALL_PINGING, &call->flags); + rxrpc_propose_ACK(call, pkt->ack.reason, + ntohs(pkt->ack.maxSkew), + 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; + bool lost = false; + int ret, opt; + + _enter(",{%d}", skb->len); + + /* 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_usage < 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; + lost = true; + goto done; + } + } + + _proto("Tx DATA %%%u { #%u }", serial, sp->hdr.seq); + + /* 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(); + + /* 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) + 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: + trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags, + retrans, lost); + if (ret >= 0) { + if (whdr.flags & RXRPC_REQUEST_ACK) { + call->peer->rtt_last_req = skb->tstamp; + trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_data, serial); + if (call->peer->rtt_usage > 1) { + unsigned long nowj = jiffies, ack_lost_at; + + ack_lost_at = nsecs_to_jiffies(2 * call->peer->rtt); + if (ack_lost_at < 1) + ack_lost_at = 1; + + 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(); + + switch (conn->params.local->srx.transport.family) { + case AF_INET6: + case AF_INET: + opt = IP_PMTUDISC_DONT; + kernel_setsockopt(conn->params.local->socket, + SOL_IP, IP_MTU_DISCOVER, + (char *)&opt, sizeof(opt)); + ret = kernel_sendmsg(conn->params.local->socket, &msg, + iov, 2, len); + conn->params.peer->last_tx_at = ktime_get_seconds(); + + opt = IP_PMTUDISC_DO; + kernel_setsockopt(conn->params.local->socket, + SOL_IP, IP_MTU_DISCOVER, + (char *)&opt, sizeof(opt)); + break; + + default: + BUG(); + } + + if (ret < 0) + 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_rx_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_rx_freed); + continue; + } + + if (rxrpc_extract_addr_from_skb(local, &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_rx_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(""); +} |