--- /dev/null
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <assert.h>
+#include <errno.h>
+#include <byteswap.h>
+#include <ipxe/timer.h>
+#include <ipxe/iobuf.h>
+#include <ipxe/malloc.h>
+#include <ipxe/init.h>
+#include <ipxe/retry.h>
+#include <ipxe/refcnt.h>
+#include <ipxe/pending.h>
+#include <ipxe/xfer.h>
+#include <ipxe/open.h>
+#include <ipxe/uri.h>
+#include <ipxe/netdevice.h>
+#include <ipxe/profile.h>
+#include <ipxe/process.h>
+#include <ipxe/tcpip.h>
+#include <ipxe/tcp.h>
+
+/** @file
+ *
+ * TCP protocol
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/** A TCP connection */
+struct tcp_connection {
+ /** Reference counter */
+ struct refcnt refcnt;
+ /** List of TCP connections */
+ struct list_head list;
+
+ /** Flags */
+ unsigned int flags;
+
+ /** Data transfer interface */
+ struct interface xfer;
+
+ /** Remote socket address */
+ struct sockaddr_tcpip peer;
+ /** Local port */
+ unsigned int local_port;
+ /** Maximum segment size */
+ size_t mss;
+
+ /** Current TCP state */
+ unsigned int tcp_state;
+ /** Previous TCP state
+ *
+ * Maintained only for debug messages
+ */
+ unsigned int prev_tcp_state;
+ /** Current sequence number
+ *
+ * Equivalent to SND.UNA in RFC 793 terminology.
+ */
+ uint32_t snd_seq;
+ /** Unacknowledged sequence count
+ *
+ * Equivalent to (SND.NXT-SND.UNA) in RFC 793 terminology.
+ */
+ uint32_t snd_sent;
+ /** Send window
+ *
+ * Equivalent to SND.WND in RFC 793 terminology
+ */
+ uint32_t snd_win;
+ /** Current acknowledgement number
+ *
+ * Equivalent to RCV.NXT in RFC 793 terminology.
+ */
+ uint32_t rcv_ack;
+ /** Receive window
+ *
+ * Equivalent to RCV.WND in RFC 793 terminology.
+ */
+ uint32_t rcv_win;
+ /** Received timestamp value
+ *
+ * Updated when a packet is received; copied to ts_recent when
+ * the window is advanced.
+ */
+ uint32_t ts_val;
+ /** Most recent received timestamp that advanced the window
+ *
+ * Equivalent to TS.Recent in RFC 1323 terminology.
+ */
+ uint32_t ts_recent;
+ /** Send window scale
+ *
+ * Equivalent to Snd.Wind.Scale in RFC 1323 terminology
+ */
+ uint8_t snd_win_scale;
+ /** Receive window scale
+ *
+ * Equivalent to Rcv.Wind.Scale in RFC 1323 terminology
+ */
+ uint8_t rcv_win_scale;
+ /** Maximum receive window */
+ uint32_t max_rcv_win;
+
+ /** Transmit queue */
+ struct list_head tx_queue;
+ /** Receive queue */
+ struct list_head rx_queue;
+ /** Transmission process */
+ struct process process;
+ /** Retransmission timer */
+ struct retry_timer timer;
+ /** Shutdown (TIME_WAIT) timer */
+ struct retry_timer wait;
+
+ /** Pending operations for SYN and FIN */
+ struct pending_operation pending_flags;
+ /** Pending operations for transmit queue */
+ struct pending_operation pending_data;
+};
+
+/** TCP flags */
+enum tcp_flags {
+ /** TCP data transfer interface has been closed */
+ TCP_XFER_CLOSED = 0x0001,
+ /** TCP timestamps are enabled */
+ TCP_TS_ENABLED = 0x0002,
+ /** TCP acknowledgement is pending */
+ TCP_ACK_PENDING = 0x0004,
+};
+
+/** TCP internal header
+ *
+ * This is the header that replaces the TCP header for packets
+ * enqueued on the receive queue.
+ */
+struct tcp_rx_queued_header {
+ /** SEQ value, in host-endian order
+ *
+ * This represents the SEQ value at the time the packet is
+ * enqueued, and so excludes the SYN, if present.
+ */
+ uint32_t seq;
+ /** Flags
+ *
+ * Only FIN is valid within this flags byte; all other flags
+ * have already been processed by the time the packet is
+ * enqueued.
+ */
+ uint8_t flags;
+ /** Reserved */
+ uint8_t reserved[3];
+};
+
+/**
+ * List of registered TCP connections
+ */
+static LIST_HEAD ( tcp_conns );
+
+/** Transmit profiler */
+static struct profiler tcp_tx_profiler __profiler = { .name = "tcp.tx" };
+
+/** Receive profiler */
+static struct profiler tcp_rx_profiler __profiler = { .name = "tcp.rx" };
+
+/** Data transfer profiler */
+static struct profiler tcp_xfer_profiler __profiler = { .name = "tcp.xfer" };
+
+/* Forward declarations */
+static struct process_descriptor tcp_process_desc;
+static struct interface_descriptor tcp_xfer_desc;
+static void tcp_expired ( struct retry_timer *timer, int over );
+static void tcp_wait_expired ( struct retry_timer *timer, int over );
+static struct tcp_connection * tcp_demux ( unsigned int local_port );
+static int tcp_rx_ack ( struct tcp_connection *tcp, uint32_t ack,
+ uint32_t win );
+
+/**
+ * Name TCP state
+ *
+ * @v state TCP state
+ * @ret name Name of TCP state
+ */
+static inline __attribute__ (( always_inline )) const char *
+tcp_state ( int state ) {
+ switch ( state ) {
+ case TCP_CLOSED: return "CLOSED";
+ case TCP_LISTEN: return "LISTEN";
+ case TCP_SYN_SENT: return "SYN_SENT";
+ case TCP_SYN_RCVD: return "SYN_RCVD";
+ case TCP_ESTABLISHED: return "ESTABLISHED";
+ case TCP_FIN_WAIT_1: return "FIN_WAIT_1";
+ case TCP_FIN_WAIT_2: return "FIN_WAIT_2";
+ case TCP_CLOSING_OR_LAST_ACK: return "CLOSING/LAST_ACK";
+ case TCP_TIME_WAIT: return "TIME_WAIT";
+ case TCP_CLOSE_WAIT: return "CLOSE_WAIT";
+ default: return "INVALID";
+ }
+}
+
+/**
+ * Dump TCP state transition
+ *
+ * @v tcp TCP connection
+ */
+static inline __attribute__ (( always_inline )) void
+tcp_dump_state ( struct tcp_connection *tcp ) {
+
+ if ( tcp->tcp_state != tcp->prev_tcp_state ) {
+ DBGC ( tcp, "TCP %p transitioned from %s to %s\n", tcp,
+ tcp_state ( tcp->prev_tcp_state ),
+ tcp_state ( tcp->tcp_state ) );
+ }
+ tcp->prev_tcp_state = tcp->tcp_state;
+}
+
+/**
+ * Dump TCP flags
+ *
+ * @v flags TCP flags
+ */
+static inline __attribute__ (( always_inline )) void
+tcp_dump_flags ( struct tcp_connection *tcp, unsigned int flags ) {
+ if ( flags & TCP_RST )
+ DBGC2 ( tcp, " RST" );
+ if ( flags & TCP_SYN )
+ DBGC2 ( tcp, " SYN" );
+ if ( flags & TCP_PSH )
+ DBGC2 ( tcp, " PSH" );
+ if ( flags & TCP_FIN )
+ DBGC2 ( tcp, " FIN" );
+ if ( flags & TCP_ACK )
+ DBGC2 ( tcp, " ACK" );
+}
+
+/***************************************************************************
+ *
+ * Open and close
+ *
+ ***************************************************************************
+ */
+
+/**
+ * Check if local TCP port is available
+ *
+ * @v port Local port number
+ * @ret port Local port number, or negative error
+ */
+static int tcp_port_available ( int port ) {
+
+ return ( tcp_demux ( port ) ? -EADDRINUSE : port );
+}
+
+/**
+ * Open a TCP connection
+ *
+ * @v xfer Data transfer interface
+ * @v peer Peer socket address
+ * @v local Local socket address, or NULL
+ * @ret rc Return status code
+ */
+static int tcp_open ( struct interface *xfer, struct sockaddr *peer,
+ struct sockaddr *local ) {
+ struct sockaddr_tcpip *st_peer = ( struct sockaddr_tcpip * ) peer;
+ struct sockaddr_tcpip *st_local = ( struct sockaddr_tcpip * ) local;
+ struct tcp_connection *tcp;
+ size_t mtu;
+ int port;
+ int rc;
+
+ /* Allocate and initialise structure */
+ tcp = zalloc ( sizeof ( *tcp ) );
+ if ( ! tcp )
+ return -ENOMEM;
+ DBGC ( tcp, "TCP %p allocated\n", tcp );
+ ref_init ( &tcp->refcnt, NULL );
+ intf_init ( &tcp->xfer, &tcp_xfer_desc, &tcp->refcnt );
+ process_init_stopped ( &tcp->process, &tcp_process_desc, &tcp->refcnt );
+ timer_init ( &tcp->timer, tcp_expired, &tcp->refcnt );
+ timer_init ( &tcp->wait, tcp_wait_expired, &tcp->refcnt );
+ tcp->prev_tcp_state = TCP_CLOSED;
+ tcp->tcp_state = TCP_STATE_SENT ( TCP_SYN );
+ tcp_dump_state ( tcp );
+ tcp->snd_seq = random();
+ tcp->max_rcv_win = TCP_MAX_WINDOW_SIZE;
+ INIT_LIST_HEAD ( &tcp->tx_queue );
+ INIT_LIST_HEAD ( &tcp->rx_queue );
+ memcpy ( &tcp->peer, st_peer, sizeof ( tcp->peer ) );
+
+ /* Calculate MSS */
+ mtu = tcpip_mtu ( &tcp->peer );
+ if ( ! mtu ) {
+ DBGC ( tcp, "TCP %p has no route to %s\n",
+ tcp, sock_ntoa ( peer ) );
+ rc = -ENETUNREACH;
+ goto err;
+ }
+ tcp->mss = ( mtu - sizeof ( struct tcp_header ) );
+
+ /* Bind to local port */
+ port = tcpip_bind ( st_local, tcp_port_available );
+ if ( port < 0 ) {
+ rc = port;
+ DBGC ( tcp, "TCP %p could not bind: %s\n",
+ tcp, strerror ( rc ) );
+ goto err;
+ }
+ tcp->local_port = port;
+ DBGC ( tcp, "TCP %p bound to port %d\n", tcp, tcp->local_port );
+
+ /* Start timer to initiate SYN */
+ start_timer_nodelay ( &tcp->timer );
+
+ /* Add a pending operation for the SYN */
+ pending_get ( &tcp->pending_flags );
+
+ /* Attach parent interface, transfer reference to connection
+ * list and return
+ */
+ intf_plug_plug ( &tcp->xfer, xfer );
+ list_add ( &tcp->list, &tcp_conns );
+ return 0;
+
+ err:
+ ref_put ( &tcp->refcnt );
+ return rc;
+}
+
+/**
+ * Close TCP connection
+ *
+ * @v tcp TCP connection
+ * @v rc Reason for close
+ *
+ * Closes the data transfer interface. If the TCP state machine is in
+ * a suitable state, the connection will be deleted.
+ */
+static void tcp_close ( struct tcp_connection *tcp, int rc ) {
+ struct io_buffer *iobuf;
+ struct io_buffer *tmp;
+
+ /* Close data transfer interface */
+ intf_shutdown ( &tcp->xfer, rc );
+ tcp->flags |= TCP_XFER_CLOSED;
+
+ /* If we are in CLOSED, or have otherwise not yet received a
+ * SYN (i.e. we are in LISTEN or SYN_SENT), just delete the
+ * connection.
+ */
+ if ( ! ( tcp->tcp_state & TCP_STATE_RCVD ( TCP_SYN ) ) ) {
+
+ /* Transition to CLOSED for the sake of debugging messages */
+ tcp->tcp_state = TCP_CLOSED;
+ tcp_dump_state ( tcp );
+
+ /* Free any unprocessed I/O buffers */
+ list_for_each_entry_safe ( iobuf, tmp, &tcp->rx_queue, list ) {
+ list_del ( &iobuf->list );
+ free_iob ( iobuf );
+ }
+
+ /* Free any unsent I/O buffers */
+ list_for_each_entry_safe ( iobuf, tmp, &tcp->tx_queue, list ) {
+ list_del ( &iobuf->list );
+ free_iob ( iobuf );
+ pending_put ( &tcp->pending_data );
+ }
+ assert ( ! is_pending ( &tcp->pending_data ) );
+
+ /* Remove pending operations for SYN and FIN, if applicable */
+ pending_put ( &tcp->pending_flags );
+ pending_put ( &tcp->pending_flags );
+
+ /* Remove from list and drop reference */
+ process_del ( &tcp->process );
+ stop_timer ( &tcp->timer );
+ stop_timer ( &tcp->wait );
+ list_del ( &tcp->list );
+ ref_put ( &tcp->refcnt );
+ DBGC ( tcp, "TCP %p connection deleted\n", tcp );
+ return;
+ }
+
+ /* If we have not had our SYN acknowledged (i.e. we are in
+ * SYN_RCVD), pretend that it has been acknowledged so that we
+ * can send a FIN without breaking things.
+ */
+ if ( ! ( tcp->tcp_state & TCP_STATE_ACKED ( TCP_SYN ) ) )
+ tcp_rx_ack ( tcp, ( tcp->snd_seq + 1 ), 0 );
+
+ /* If we have no data remaining to send, start sending FIN */
+ if ( list_empty ( &tcp->tx_queue ) &&
+ ! ( tcp->tcp_state & TCP_STATE_SENT ( TCP_FIN ) ) ) {
+
+ tcp->tcp_state |= TCP_STATE_SENT ( TCP_FIN );
+ tcp_dump_state ( tcp );
+
+ /* Add a pending operation for the FIN */
+ pending_get ( &tcp->pending_flags );
+ }
+}
+
+/***************************************************************************
+ *
+ * Transmit data path
+ *
+ ***************************************************************************
+ */
+
+/**
+ * Calculate transmission window
+ *
+ * @v tcp TCP connection
+ * @ret len Maximum length that can be sent in a single packet
+ */
+static size_t tcp_xmit_win ( struct tcp_connection *tcp ) {
+ size_t len;
+
+ /* Not ready if we're not in a suitable connection state */
+ if ( ! TCP_CAN_SEND_DATA ( tcp->tcp_state ) )
+ return 0;
+
+ /* Length is the minimum of the receiver's window and the path MTU */
+ len = tcp->snd_win;
+ if ( len > TCP_PATH_MTU )
+ len = TCP_PATH_MTU;
+
+ return len;
+}
+
+/**
+ * Check data-transfer flow control window
+ *
+ * @v tcp TCP connection
+ * @ret len Length of window
+ */
+static size_t tcp_xfer_window ( struct tcp_connection *tcp ) {
+
+ /* Not ready if data queue is non-empty. This imposes a limit
+ * of only one unACKed packet in the TX queue at any time; we
+ * do this to conserve memory usage.
+ */
+ if ( ! list_empty ( &tcp->tx_queue ) )
+ return 0;
+
+ /* Return TCP window length */
+ return tcp_xmit_win ( tcp );
+}
+
+/**
+ * Process TCP transmit queue
+ *
+ * @v tcp TCP connection
+ * @v max_len Maximum length to process
+ * @v dest I/O buffer to fill with data, or NULL
+ * @v remove Remove data from queue
+ * @ret len Length of data processed
+ *
+ * This processes at most @c max_len bytes from the TCP connection's
+ * transmit queue. Data will be copied into the @c dest I/O buffer
+ * (if provided) and, if @c remove is true, removed from the transmit
+ * queue.
+ */
+static size_t tcp_process_tx_queue ( struct tcp_connection *tcp, size_t max_len,
+ struct io_buffer *dest, int remove ) {
+ struct io_buffer *iobuf;
+ struct io_buffer *tmp;
+ size_t frag_len;
+ size_t len = 0;
+
+ list_for_each_entry_safe ( iobuf, tmp, &tcp->tx_queue, list ) {
+ frag_len = iob_len ( iobuf );
+ if ( frag_len > max_len )
+ frag_len = max_len;
+ if ( dest ) {
+ memcpy ( iob_put ( dest, frag_len ), iobuf->data,
+ frag_len );
+ }
+ if ( remove ) {
+ iob_pull ( iobuf, frag_len );
+ if ( ! iob_len ( iobuf ) ) {
+ list_del ( &iobuf->list );
+ free_iob ( iobuf );
+ pending_put ( &tcp->pending_data );
+ }
+ }
+ len += frag_len;
+ max_len -= frag_len;
+ }
+ return len;
+}
+
+/**
+ * Transmit any outstanding data
+ *
+ * @v tcp TCP connection
+ *
+ * Transmits any outstanding data on the connection.
+ *
+ * Note that even if an error is returned, the retransmission timer
+ * will have been started if necessary, and so the stack will
+ * eventually attempt to retransmit the failed packet.
+ */
+static void tcp_xmit ( struct tcp_connection *tcp ) {
+ struct io_buffer *iobuf;
+ struct tcp_header *tcphdr;
+ struct tcp_mss_option *mssopt;
+ struct tcp_window_scale_padded_option *wsopt;
+ struct tcp_timestamp_padded_option *tsopt;
+ void *payload;
+ unsigned int flags;
+ size_t len = 0;
+ uint32_t seq_len;
+ uint32_t app_win;
+ uint32_t max_rcv_win;
+ uint32_t max_representable_win;
+ int rc;
+
+ /* Start profiling */
+ profile_start ( &tcp_tx_profiler );
+
+ /* If retransmission timer is already running, do nothing */
+ if ( timer_running ( &tcp->timer ) )
+ return;
+
+ /* Calculate both the actual (payload) and sequence space
+ * lengths that we wish to transmit.
+ */
+ if ( TCP_CAN_SEND_DATA ( tcp->tcp_state ) ) {
+ len = tcp_process_tx_queue ( tcp, tcp_xmit_win ( tcp ),
+ NULL, 0 );
+ }
+ seq_len = len;
+ flags = TCP_FLAGS_SENDING ( tcp->tcp_state );
+ if ( flags & ( TCP_SYN | TCP_FIN ) ) {
+ /* SYN or FIN consume one byte, and we can never send both */
+ assert ( ! ( ( flags & TCP_SYN ) && ( flags & TCP_FIN ) ) );
+ seq_len++;
+ }
+ tcp->snd_sent = seq_len;
+
+ /* If we have nothing to transmit, stop now */
+ if ( ( seq_len == 0 ) && ! ( tcp->flags & TCP_ACK_PENDING ) )
+ return;
+
+ /* If we are transmitting anything that requires
+ * acknowledgement (i.e. consumes sequence space), start the
+ * retransmission timer. Do this before attempting to
+ * allocate the I/O buffer, in case allocation itself fails.
+ */
+ if ( seq_len )
+ start_timer ( &tcp->timer );
+
+ /* Allocate I/O buffer */
+ iobuf = alloc_iob ( len + TCP_MAX_HEADER_LEN );
+ if ( ! iobuf ) {
+ DBGC ( tcp, "TCP %p could not allocate iobuf for %08x..%08x "
+ "%08x\n", tcp, tcp->snd_seq, ( tcp->snd_seq + seq_len ),
+ tcp->rcv_ack );
+ return;
+ }
+ iob_reserve ( iobuf, TCP_MAX_HEADER_LEN );
+
+ /* Fill data payload from transmit queue */
+ tcp_process_tx_queue ( tcp, len, iobuf, 0 );
+
+ /* Expand receive window if possible */
+ max_rcv_win = tcp->max_rcv_win;
+ app_win = xfer_window ( &tcp->xfer );
+ if ( max_rcv_win > app_win )
+ max_rcv_win = app_win;
+ max_representable_win = ( 0xffff << tcp->rcv_win_scale );
+ if ( max_rcv_win > max_representable_win )
+ max_rcv_win = max_representable_win;
+ max_rcv_win &= ~0x03; /* Keep everything dword-aligned */
+ if ( tcp->rcv_win < max_rcv_win )
+ tcp->rcv_win = max_rcv_win;
+
+ /* Fill up the TCP header */
+ payload = iobuf->data;
+ if ( flags & TCP_SYN ) {
+ mssopt = iob_push ( iobuf, sizeof ( *mssopt ) );
+ mssopt->kind = TCP_OPTION_MSS;
+ mssopt->length = sizeof ( *mssopt );
+ mssopt->mss = htons ( tcp->mss );
+ wsopt = iob_push ( iobuf, sizeof ( *wsopt ) );
+ wsopt->nop = TCP_OPTION_NOP;
+ wsopt->wsopt.kind = TCP_OPTION_WS;
+ wsopt->wsopt.length = sizeof ( wsopt->wsopt );
+ wsopt->wsopt.scale = TCP_RX_WINDOW_SCALE;
+ }
+ if ( ( flags & TCP_SYN ) || ( tcp->flags & TCP_TS_ENABLED ) ) {
+ tsopt = iob_push ( iobuf, sizeof ( *tsopt ) );
+ memset ( tsopt->nop, TCP_OPTION_NOP, sizeof ( tsopt->nop ) );
+ tsopt->tsopt.kind = TCP_OPTION_TS;
+ tsopt->tsopt.length = sizeof ( tsopt->tsopt );
+ tsopt->tsopt.tsval = htonl ( currticks() );
+ tsopt->tsopt.tsecr = htonl ( tcp->ts_recent );
+ }
+ if ( len != 0 )
+ flags |= TCP_PSH;
+ tcphdr = iob_push ( iobuf, sizeof ( *tcphdr ) );
+ memset ( tcphdr, 0, sizeof ( *tcphdr ) );
+ tcphdr->src = htons ( tcp->local_port );
+ tcphdr->dest = tcp->peer.st_port;
+ tcphdr->seq = htonl ( tcp->snd_seq );
+ tcphdr->ack = htonl ( tcp->rcv_ack );
+ tcphdr->hlen = ( ( payload - iobuf->data ) << 2 );
+ tcphdr->flags = flags;
+ tcphdr->win = htons ( tcp->rcv_win >> tcp->rcv_win_scale );
+ tcphdr->csum = tcpip_chksum ( iobuf->data, iob_len ( iobuf ) );
+
+ /* Dump header */
+ DBGC2 ( tcp, "TCP %p TX %d->%d %08x..%08x %08x %4zd",
+ tcp, ntohs ( tcphdr->src ), ntohs ( tcphdr->dest ),
+ ntohl ( tcphdr->seq ), ( ntohl ( tcphdr->seq ) + seq_len ),
+ ntohl ( tcphdr->ack ), len );
+ tcp_dump_flags ( tcp, tcphdr->flags );
+ DBGC2 ( tcp, "\n" );
+
+ /* Transmit packet */
+ if ( ( rc = tcpip_tx ( iobuf, &tcp_protocol, NULL, &tcp->peer, NULL,
+ &tcphdr->csum ) ) != 0 ) {
+ DBGC ( tcp, "TCP %p could not transmit %08x..%08x %08x: %s\n",
+ tcp, tcp->snd_seq, ( tcp->snd_seq + tcp->snd_sent ),
+ tcp->rcv_ack, strerror ( rc ) );
+ return;
+ }
+
+ /* Clear ACK-pending flag */
+ tcp->flags &= ~TCP_ACK_PENDING;
+
+ profile_stop ( &tcp_tx_profiler );
+}
+
+/** TCP process descriptor */
+static struct process_descriptor tcp_process_desc =
+ PROC_DESC_ONCE ( struct tcp_connection, process, tcp_xmit );
+
+/**
+ * Retransmission timer expired
+ *
+ * @v timer Retransmission timer
+ * @v over Failure indicator
+ */
+static void tcp_expired ( struct retry_timer *timer, int over ) {
+ struct tcp_connection *tcp =
+ container_of ( timer, struct tcp_connection, timer );
+
+ DBGC ( tcp, "TCP %p timer %s in %s for %08x..%08x %08x\n", tcp,
+ ( over ? "expired" : "fired" ), tcp_state ( tcp->tcp_state ),
+ tcp->snd_seq, ( tcp->snd_seq + tcp->snd_sent ), tcp->rcv_ack );
+
+ assert ( ( tcp->tcp_state == TCP_SYN_SENT ) ||
+ ( tcp->tcp_state == TCP_SYN_RCVD ) ||
+ ( tcp->tcp_state == TCP_ESTABLISHED ) ||
+ ( tcp->tcp_state == TCP_FIN_WAIT_1 ) ||
+ ( tcp->tcp_state == TCP_CLOSE_WAIT ) ||
+ ( tcp->tcp_state == TCP_CLOSING_OR_LAST_ACK ) );
+
+ if ( over ) {
+ /* If we have finally timed out and given up,
+ * terminate the connection
+ */
+ tcp->tcp_state = TCP_CLOSED;
+ tcp_dump_state ( tcp );
+ tcp_close ( tcp, -ETIMEDOUT );
+ } else {
+ /* Otherwise, retransmit the packet */
+ tcp_xmit ( tcp );
+ }
+}
+
+/**
+ * Shutdown timer expired
+ *
+ * @v timer Shutdown timer
+ * @v over Failure indicator
+ */
+static void tcp_wait_expired ( struct retry_timer *timer, int over __unused ) {
+ struct tcp_connection *tcp =
+ container_of ( timer, struct tcp_connection, wait );
+
+ assert ( tcp->tcp_state == TCP_TIME_WAIT );
+
+ DBGC ( tcp, "TCP %p wait complete in %s for %08x..%08x %08x\n", tcp,
+ tcp_state ( tcp->tcp_state ), tcp->snd_seq,
+ ( tcp->snd_seq + tcp->snd_sent ), tcp->rcv_ack );
+
+ tcp->tcp_state = TCP_CLOSED;
+ tcp_dump_state ( tcp );
+ tcp_close ( tcp, 0 );
+}
+
+/**
+ * Send RST response to incoming packet
+ *
+ * @v in_tcphdr TCP header of incoming packet
+ * @ret rc Return status code
+ */
+static int tcp_xmit_reset ( struct tcp_connection *tcp,
+ struct sockaddr_tcpip *st_dest,
+ struct tcp_header *in_tcphdr ) {
+ struct io_buffer *iobuf;
+ struct tcp_header *tcphdr;
+ int rc;
+
+ /* Allocate space for dataless TX buffer */
+ iobuf = alloc_iob ( TCP_MAX_HEADER_LEN );
+ if ( ! iobuf ) {
+ DBGC ( tcp, "TCP %p could not allocate iobuf for RST "
+ "%08x..%08x %08x\n", tcp, ntohl ( in_tcphdr->ack ),
+ ntohl ( in_tcphdr->ack ), ntohl ( in_tcphdr->seq ) );
+ return -ENOMEM;
+ }
+ iob_reserve ( iobuf, TCP_MAX_HEADER_LEN );
+
+ /* Construct RST response */
+ tcphdr = iob_push ( iobuf, sizeof ( *tcphdr ) );
+ memset ( tcphdr, 0, sizeof ( *tcphdr ) );
+ tcphdr->src = in_tcphdr->dest;
+ tcphdr->dest = in_tcphdr->src;
+ tcphdr->seq = in_tcphdr->ack;
+ tcphdr->ack = in_tcphdr->seq;
+ tcphdr->hlen = ( ( sizeof ( *tcphdr ) / 4 ) << 4 );
+ tcphdr->flags = ( TCP_RST | TCP_ACK );
+ tcphdr->win = htons ( 0 );
+ tcphdr->csum = tcpip_chksum ( iobuf->data, iob_len ( iobuf ) );
+
+ /* Dump header */
+ DBGC2 ( tcp, "TCP %p TX %d->%d %08x..%08x %08x %4d",
+ tcp, ntohs ( tcphdr->src ), ntohs ( tcphdr->dest ),
+ ntohl ( tcphdr->seq ), ( ntohl ( tcphdr->seq ) ),
+ ntohl ( tcphdr->ack ), 0 );
+ tcp_dump_flags ( tcp, tcphdr->flags );
+ DBGC2 ( tcp, "\n" );
+
+ /* Transmit packet */
+ if ( ( rc = tcpip_tx ( iobuf, &tcp_protocol, NULL, st_dest,
+ NULL, &tcphdr->csum ) ) != 0 ) {
+ DBGC ( tcp, "TCP %p could not transmit RST %08x..%08x %08x: "
+ "%s\n", tcp, ntohl ( in_tcphdr->ack ),
+ ntohl ( in_tcphdr->ack ), ntohl ( in_tcphdr->seq ),
+ strerror ( rc ) );
+ return rc;
+ }
+
+ return 0;
+}
+
+/***************************************************************************
+ *
+ * Receive data path
+ *
+ ***************************************************************************
+ */
+
+/**
+ * Identify TCP connection by local port number
+ *
+ * @v local_port Local port
+ * @ret tcp TCP connection, or NULL
+ */
+static struct tcp_connection * tcp_demux ( unsigned int local_port ) {
+ struct tcp_connection *tcp;
+
+ list_for_each_entry ( tcp, &tcp_conns, list ) {
+ if ( tcp->local_port == local_port )
+ return tcp;
+ }
+ return NULL;
+}
+
+/**
+ * Parse TCP received options
+ *
+ * @v tcp TCP connection
+ * @v data Raw options data
+ * @v len Raw options length
+ * @v options Options structure to fill in
+ */
+static void tcp_rx_opts ( struct tcp_connection *tcp, const void *data,
+ size_t len, struct tcp_options *options ) {
+ const void *end = ( data + len );
+ const struct tcp_option *option;
+ unsigned int kind;
+
+ memset ( options, 0, sizeof ( *options ) );
+ while ( data < end ) {
+ option = data;
+ kind = option->kind;
+ if ( kind == TCP_OPTION_END )
+ return;
+ if ( kind == TCP_OPTION_NOP ) {
+ data++;
+ continue;
+ }
+ switch ( kind ) {
+ case TCP_OPTION_MSS:
+ options->mssopt = data;
+ break;
+ case TCP_OPTION_WS:
+ options->wsopt = data;
+ break;
+ case TCP_OPTION_TS:
+ options->tsopt = data;
+ break;
+ default:
+ DBGC ( tcp, "TCP %p received unknown option %d\n",
+ tcp, kind );
+ break;
+ }
+ data += option->length;
+ }
+}
+
+/**
+ * Consume received sequence space
+ *
+ * @v tcp TCP connection
+ * @v seq_len Sequence space length to consume
+ */
+static void tcp_rx_seq ( struct tcp_connection *tcp, uint32_t seq_len ) {
+
+ /* Sanity check */
+ assert ( seq_len > 0 );
+
+ /* Update acknowledgement number */
+ tcp->rcv_ack += seq_len;
+
+ /* Update window */
+ if ( tcp->rcv_win > seq_len ) {
+ tcp->rcv_win -= seq_len;
+ } else {
+ tcp->rcv_win = 0;
+ }
+
+ /* Update timestamp */
+ tcp->ts_recent = tcp->ts_val;
+
+ /* Mark ACK as pending */
+ tcp->flags |= TCP_ACK_PENDING;
+}
+
+/**
+ * Handle TCP received SYN
+ *
+ * @v tcp TCP connection
+ * @v seq SEQ value (in host-endian order)
+ * @v options TCP options
+ * @ret rc Return status code
+ */
+static int tcp_rx_syn ( struct tcp_connection *tcp, uint32_t seq,
+ struct tcp_options *options ) {
+
+ /* Synchronise sequence numbers on first SYN */
+ if ( ! ( tcp->tcp_state & TCP_STATE_RCVD ( TCP_SYN ) ) ) {
+ tcp->rcv_ack = seq;
+ if ( options->tsopt )
+ tcp->flags |= TCP_TS_ENABLED;
+ if ( options->wsopt ) {
+ tcp->snd_win_scale = options->wsopt->scale;
+ tcp->rcv_win_scale = TCP_RX_WINDOW_SCALE;
+ }
+ }
+
+ /* Ignore duplicate SYN */
+ if ( seq != tcp->rcv_ack )
+ return 0;
+
+ /* Acknowledge SYN */
+ tcp_rx_seq ( tcp, 1 );
+
+ /* Mark SYN as received and start sending ACKs with each packet */
+ tcp->tcp_state |= ( TCP_STATE_SENT ( TCP_ACK ) |
+ TCP_STATE_RCVD ( TCP_SYN ) );
+
+ return 0;
+}
+
+/**
+ * Handle TCP received ACK
+ *
+ * @v tcp TCP connection
+ * @v ack ACK value (in host-endian order)
+ * @v win WIN value (in host-endian order)
+ * @ret rc Return status code
+ */
+static int tcp_rx_ack ( struct tcp_connection *tcp, uint32_t ack,
+ uint32_t win ) {
+ uint32_t ack_len = ( ack - tcp->snd_seq );
+ size_t len;
+ unsigned int acked_flags;
+
+ /* Check for out-of-range or old duplicate ACKs */
+ if ( ack_len > tcp->snd_sent ) {
+ DBGC ( tcp, "TCP %p received ACK for %08x..%08x, "
+ "sent only %08x..%08x\n", tcp, tcp->snd_seq,
+ ( tcp->snd_seq + ack_len ), tcp->snd_seq,
+ ( tcp->snd_seq + tcp->snd_sent ) );
+
+ if ( TCP_HAS_BEEN_ESTABLISHED ( tcp->tcp_state ) ) {
+ /* Just ignore what might be old duplicate ACKs */
+ return 0;
+ } else {
+ /* Send RST if an out-of-range ACK is received
+ * on a not-yet-established connection, as per
+ * RFC 793.
+ */
+ return -EINVAL;
+ }
+ }
+
+ /* Update window size */
+ tcp->snd_win = win;
+
+ /* Ignore ACKs that don't actually acknowledge any new data.
+ * (In particular, do not stop the retransmission timer; this
+ * avoids creating a sorceror's apprentice syndrome when a
+ * duplicate ACK is received and we still have data in our
+ * transmit queue.)
+ */
+ if ( ack_len == 0 )
+ return 0;
+
+ /* Stop the retransmission timer */
+ stop_timer ( &tcp->timer );
+
+ /* Determine acknowledged flags and data length */
+ len = ack_len;
+ acked_flags = ( TCP_FLAGS_SENDING ( tcp->tcp_state ) &
+ ( TCP_SYN | TCP_FIN ) );
+ if ( acked_flags ) {
+ len--;
+ pending_put ( &tcp->pending_flags );
+ }
+
+ /* Update SEQ and sent counters */
+ tcp->snd_seq = ack;
+ tcp->snd_sent = 0;
+
+ /* Remove any acknowledged data from transmit queue */
+ tcp_process_tx_queue ( tcp, len, NULL, 1 );
+
+ /* Mark SYN/FIN as acknowledged if applicable. */
+ if ( acked_flags )
+ tcp->tcp_state |= TCP_STATE_ACKED ( acked_flags );
+
+ /* Start sending FIN if we've had all possible data ACKed */
+ if ( list_empty ( &tcp->tx_queue ) &&
+ ( tcp->flags & TCP_XFER_CLOSED ) &&
+ ! ( tcp->tcp_state & TCP_STATE_SENT ( TCP_FIN ) ) ) {
+ tcp->tcp_state |= TCP_STATE_SENT ( TCP_FIN );
+ pending_get ( &tcp->pending_flags );
+ }
+
+ return 0;
+}
+
+/**
+ * Handle TCP received data
+ *
+ * @v tcp TCP connection
+ * @v seq SEQ value (in host-endian order)
+ * @v iobuf I/O buffer
+ * @ret rc Return status code
+ *
+ * This function takes ownership of the I/O buffer.
+ */
+static int tcp_rx_data ( struct tcp_connection *tcp, uint32_t seq,
+ struct io_buffer *iobuf ) {
+ uint32_t already_rcvd;
+ uint32_t len;
+ int rc;
+
+ /* Ignore duplicate or out-of-order data */
+ already_rcvd = ( tcp->rcv_ack - seq );
+ len = iob_len ( iobuf );
+ if ( already_rcvd >= len ) {
+ free_iob ( iobuf );
+ return 0;
+ }
+ iob_pull ( iobuf, already_rcvd );
+ len -= already_rcvd;
+
+ /* Acknowledge new data */
+ tcp_rx_seq ( tcp, len );
+
+ /* Deliver data to application */
+ profile_start ( &tcp_xfer_profiler );
+ if ( ( rc = xfer_deliver_iob ( &tcp->xfer, iobuf ) ) != 0 ) {
+ DBGC ( tcp, "TCP %p could not deliver %08x..%08x: %s\n",
+ tcp, seq, ( seq + len ), strerror ( rc ) );
+ return rc;
+ }
+ profile_stop ( &tcp_xfer_profiler );
+
+ return 0;
+}
+
+/**
+ * Handle TCP received FIN
+ *
+ * @v tcp TCP connection
+ * @v seq SEQ value (in host-endian order)
+ * @ret rc Return status code
+ */
+static int tcp_rx_fin ( struct tcp_connection *tcp, uint32_t seq ) {
+
+ /* Ignore duplicate or out-of-order FIN */
+ if ( seq != tcp->rcv_ack )
+ return 0;
+
+ /* Acknowledge FIN */
+ tcp_rx_seq ( tcp, 1 );
+
+ /* Mark FIN as received */
+ tcp->tcp_state |= TCP_STATE_RCVD ( TCP_FIN );
+
+ /* Close connection */
+ tcp_close ( tcp, 0 );
+
+ return 0;
+}
+
+/**
+ * Handle TCP received RST
+ *
+ * @v tcp TCP connection
+ * @v seq SEQ value (in host-endian order)
+ * @ret rc Return status code
+ */
+static int tcp_rx_rst ( struct tcp_connection *tcp, uint32_t seq ) {
+
+ /* Accept RST only if it falls within the window. If we have
+ * not yet received a SYN, then we have no window to test
+ * against, so fall back to checking that our SYN has been
+ * ACKed.
+ */
+ if ( tcp->tcp_state & TCP_STATE_RCVD ( TCP_SYN ) ) {
+ if ( ! tcp_in_window ( seq, tcp->rcv_ack, tcp->rcv_win ) )
+ return 0;
+ } else {
+ if ( ! ( tcp->tcp_state & TCP_STATE_ACKED ( TCP_SYN ) ) )
+ return 0;
+ }
+
+ /* Abort connection */
+ tcp->tcp_state = TCP_CLOSED;
+ tcp_dump_state ( tcp );
+ tcp_close ( tcp, -ECONNRESET );
+
+ DBGC ( tcp, "TCP %p connection reset by peer\n", tcp );
+ return -ECONNRESET;
+}
+
+/**
+ * Enqueue received TCP packet
+ *
+ * @v tcp TCP connection
+ * @v seq SEQ value (in host-endian order)
+ * @v flags TCP flags
+ * @v iobuf I/O buffer
+ */
+static void tcp_rx_enqueue ( struct tcp_connection *tcp, uint32_t seq,
+ uint8_t flags, struct io_buffer *iobuf ) {
+ struct tcp_rx_queued_header *tcpqhdr;
+ struct io_buffer *queued;
+ size_t len;
+ uint32_t seq_len;
+
+ /* Calculate remaining flags and sequence length. Note that
+ * SYN, if present, has already been processed by this point.
+ */
+ flags &= TCP_FIN;
+ len = iob_len ( iobuf );
+ seq_len = ( len + ( flags ? 1 : 0 ) );
+
+ /* Discard immediately (to save memory) if:
+ *
+ * a) we have not yet received a SYN (and so have no defined
+ * receive window), or
+ * b) the packet lies entirely outside the receive window, or
+ * c) there is no further content to process.
+ */
+ if ( ( ! ( tcp->tcp_state & TCP_STATE_RCVD ( TCP_SYN ) ) ) ||
+ ( tcp_cmp ( seq, tcp->rcv_ack + tcp->rcv_win ) >= 0 ) ||
+ ( tcp_cmp ( seq + seq_len, tcp->rcv_ack ) < 0 ) ||
+ ( seq_len == 0 ) ) {
+ free_iob ( iobuf );
+ return;
+ }
+
+ /* Add internal header */
+ tcpqhdr = iob_push ( iobuf, sizeof ( *tcpqhdr ) );
+ tcpqhdr->seq = seq;
+ tcpqhdr->flags = flags;
+
+ /* Add to RX queue */
+ list_for_each_entry ( queued, &tcp->rx_queue, list ) {
+ tcpqhdr = queued->data;
+ if ( tcp_cmp ( seq, tcpqhdr->seq ) < 0 )
+ break;
+ }
+ list_add_tail ( &iobuf->list, &queued->list );
+}
+
+/**
+ * Process receive queue
+ *
+ * @v tcp TCP connection
+ */
+static void tcp_process_rx_queue ( struct tcp_connection *tcp ) {
+ struct io_buffer *iobuf;
+ struct tcp_rx_queued_header *tcpqhdr;
+ uint32_t seq;
+ unsigned int flags;
+ size_t len;
+
+ /* Process all applicable received buffers. Note that we
+ * cannot use list_for_each_entry() to iterate over the RX
+ * queue, since tcp_discard() may remove packets from the RX
+ * queue while we are processing.
+ */
+ while ( ( iobuf = list_first_entry ( &tcp->rx_queue, struct io_buffer,
+ list ) ) ) {
+
+ /* Stop processing when we hit the first gap */
+ tcpqhdr = iobuf->data;
+ if ( tcp_cmp ( tcpqhdr->seq, tcp->rcv_ack ) > 0 )
+ break;
+
+ /* Strip internal header and remove from RX queue */
+ list_del ( &iobuf->list );
+ seq = tcpqhdr->seq;
+ flags = tcpqhdr->flags;
+ iob_pull ( iobuf, sizeof ( *tcpqhdr ) );
+ len = iob_len ( iobuf );
+
+ /* Handle new data, if any */
+ tcp_rx_data ( tcp, seq, iob_disown ( iobuf ) );
+ seq += len;
+
+ /* Handle FIN, if present */
+ if ( flags & TCP_FIN ) {
+ tcp_rx_fin ( tcp, seq );
+ seq++;
+ }
+ }
+}
+
+/**
+ * Process received packet
+ *
+ * @v iobuf I/O buffer
+ * @v netdev Network device
+ * @v st_src Partially-filled source address
+ * @v st_dest Partially-filled destination address
+ * @v pshdr_csum Pseudo-header checksum
+ * @ret rc Return status code
+ */
+static int tcp_rx ( struct io_buffer *iobuf,
+ struct net_device *netdev __unused,
+ struct sockaddr_tcpip *st_src,
+ struct sockaddr_tcpip *st_dest __unused,
+ uint16_t pshdr_csum ) {
+ struct tcp_header *tcphdr = iobuf->data;
+ struct tcp_connection *tcp;
+ struct tcp_options options;
+ size_t hlen;
+ uint16_t csum;
+ uint32_t seq;
+ uint32_t ack;
+ uint16_t raw_win;
+ uint32_t win;
+ unsigned int flags;
+ size_t len;
+ uint32_t seq_len;
+ size_t old_xfer_window;
+ int rc;
+
+ /* Start profiling */
+ profile_start ( &tcp_rx_profiler );
+
+ /* Sanity check packet */
+ if ( iob_len ( iobuf ) < sizeof ( *tcphdr ) ) {
+ DBG ( "TCP packet too short at %zd bytes (min %zd bytes)\n",
+ iob_len ( iobuf ), sizeof ( *tcphdr ) );
+ rc = -EINVAL;
+ goto discard;
+ }
+ hlen = ( ( tcphdr->hlen & TCP_MASK_HLEN ) / 16 ) * 4;
+ if ( hlen < sizeof ( *tcphdr ) ) {
+ DBG ( "TCP header too short at %zd bytes (min %zd bytes)\n",
+ hlen, sizeof ( *tcphdr ) );
+ rc = -EINVAL;
+ goto discard;
+ }
+ if ( hlen > iob_len ( iobuf ) ) {
+ DBG ( "TCP header too long at %zd bytes (max %zd bytes)\n",
+ hlen, iob_len ( iobuf ) );
+ rc = -EINVAL;
+ goto discard;
+ }
+ csum = tcpip_continue_chksum ( pshdr_csum, iobuf->data,
+ iob_len ( iobuf ) );
+ if ( csum != 0 ) {
+ DBG ( "TCP checksum incorrect (is %04x including checksum "
+ "field, should be 0000)\n", csum );
+ rc = -EINVAL;
+ goto discard;
+ }
+
+ /* Parse parameters from header and strip header */
+ tcp = tcp_demux ( ntohs ( tcphdr->dest ) );
+ seq = ntohl ( tcphdr->seq );
+ ack = ntohl ( tcphdr->ack );
+ raw_win = ntohs ( tcphdr->win );
+ flags = tcphdr->flags;
+ tcp_rx_opts ( tcp, ( ( ( void * ) tcphdr ) + sizeof ( *tcphdr ) ),
+ ( hlen - sizeof ( *tcphdr ) ), &options );
+ if ( tcp && options.tsopt )
+ tcp->ts_val = ntohl ( options.tsopt->tsval );
+ iob_pull ( iobuf, hlen );
+ len = iob_len ( iobuf );
+ seq_len = ( len + ( ( flags & TCP_SYN ) ? 1 : 0 ) +
+ ( ( flags & TCP_FIN ) ? 1 : 0 ) );
+
+ /* Dump header */
+ DBGC2 ( tcp, "TCP %p RX %d<-%d %08x %08x..%08x %4zd",
+ tcp, ntohs ( tcphdr->dest ), ntohs ( tcphdr->src ),
+ ntohl ( tcphdr->ack ), ntohl ( tcphdr->seq ),
+ ( ntohl ( tcphdr->seq ) + seq_len ), len );
+ tcp_dump_flags ( tcp, tcphdr->flags );
+ DBGC2 ( tcp, "\n" );
+
+ /* If no connection was found, silently drop packet */
+ if ( ! tcp ) {
+ rc = -ENOTCONN;
+ goto discard;
+ }
+
+ /* Record old data-transfer window */
+ old_xfer_window = tcp_xfer_window ( tcp );
+
+ /* Handle ACK, if present */
+ if ( flags & TCP_ACK ) {
+ win = ( raw_win << tcp->snd_win_scale );
+ if ( ( rc = tcp_rx_ack ( tcp, ack, win ) ) != 0 ) {
+ tcp_xmit_reset ( tcp, st_src, tcphdr );
+ goto discard;
+ }
+ }
+
+ /* Force an ACK if this packet is out of order */
+ if ( ( tcp->tcp_state & TCP_STATE_RCVD ( TCP_SYN ) ) &&
+ ( seq != tcp->rcv_ack ) ) {
+ tcp->flags |= TCP_ACK_PENDING;
+ }
+
+ /* Handle SYN, if present */
+ if ( flags & TCP_SYN ) {
+ tcp_rx_syn ( tcp, seq, &options );
+ seq++;
+ }
+
+ /* Handle RST, if present */
+ if ( flags & TCP_RST ) {
+ if ( ( rc = tcp_rx_rst ( tcp, seq ) ) != 0 )
+ goto discard;
+ }
+
+ /* Enqueue received data */
+ tcp_rx_enqueue ( tcp, seq, flags, iob_disown ( iobuf ) );
+
+ /* Process receive queue */
+ tcp_process_rx_queue ( tcp );
+
+ /* Dump out any state change as a result of the received packet */
+ tcp_dump_state ( tcp );
+
+ /* Schedule transmission of ACK (and any pending data). If we
+ * have received any out-of-order packets (i.e. if the receive
+ * queue remains non-empty after processing) then send the ACK
+ * immediately in order to trigger Fast Retransmission.
+ */
+ if ( list_empty ( &tcp->rx_queue ) ) {
+ process_add ( &tcp->process );
+ } else {
+ tcp_xmit ( tcp );
+ }
+
+ /* If this packet was the last we expect to receive, set up
+ * timer to expire and cause the connection to be freed.
+ */
+ if ( TCP_CLOSED_GRACEFULLY ( tcp->tcp_state ) ) {
+ stop_timer ( &tcp->wait );
+ start_timer_fixed ( &tcp->wait, ( 2 * TCP_MSL ) );
+ }
+
+ /* Notify application if window has changed */
+ if ( tcp_xfer_window ( tcp ) != old_xfer_window )
+ xfer_window_changed ( &tcp->xfer );
+
+ profile_stop ( &tcp_rx_profiler );
+ return 0;
+
+ discard:
+ /* Free received packet */
+ free_iob ( iobuf );
+ return rc;
+}
+
+/** TCP protocol */
+struct tcpip_protocol tcp_protocol __tcpip_protocol = {
+ .name = "TCP",
+ .rx = tcp_rx,
+ .tcpip_proto = IP_TCP,
+};
+
+/**
+ * Discard some cached TCP data
+ *
+ * @ret discarded Number of cached items discarded
+ */
+static unsigned int tcp_discard ( void ) {
+ struct tcp_connection *tcp;
+ struct io_buffer *iobuf;
+ struct tcp_rx_queued_header *tcpqhdr;
+ uint32_t max_win;
+ unsigned int discarded = 0;
+
+ /* Try to drop one queued RX packet from each connection */
+ list_for_each_entry ( tcp, &tcp_conns, list ) {
+ list_for_each_entry_reverse ( iobuf, &tcp->rx_queue, list ) {
+
+ /* Limit window to prevent future discards */
+ tcpqhdr = iobuf->data;
+ max_win = ( tcpqhdr->seq - tcp->rcv_ack );
+ if ( max_win < tcp->max_rcv_win ) {
+ DBGC ( tcp, "TCP %p reducing maximum window "
+ "from %d to %d\n",
+ tcp, tcp->max_rcv_win, max_win );
+ tcp->max_rcv_win = max_win;
+ }
+
+ /* Remove packet from queue */
+ list_del ( &iobuf->list );
+ free_iob ( iobuf );
+
+ /* Report discard */
+ discarded++;
+ break;
+ }
+ }
+
+ return discarded;
+}
+
+/** TCP cache discarder */
+struct cache_discarder tcp_discarder __cache_discarder ( CACHE_NORMAL ) = {
+ .discard = tcp_discard,
+};
+
+/**
+ * Shut down all TCP connections
+ *
+ */
+static void tcp_shutdown ( int booting __unused ) {
+ struct tcp_connection *tcp;
+
+ while ( ( tcp = list_first_entry ( &tcp_conns, struct tcp_connection,
+ list ) ) != NULL ) {
+ tcp->tcp_state = TCP_CLOSED;
+ tcp_dump_state ( tcp );
+ tcp_close ( tcp, -ECANCELED );
+ }
+}
+
+/** TCP shutdown function */
+struct startup_fn tcp_startup_fn __startup_fn ( STARTUP_EARLY ) = {
+ .shutdown = tcp_shutdown,
+};
+
+/***************************************************************************
+ *
+ * Data transfer interface
+ *
+ ***************************************************************************
+ */
+
+/**
+ * Close interface
+ *
+ * @v tcp TCP connection
+ * @v rc Reason for close
+ */
+static void tcp_xfer_close ( struct tcp_connection *tcp, int rc ) {
+
+ /* Close data transfer interface */
+ tcp_close ( tcp, rc );
+
+ /* Transmit FIN, if possible */
+ tcp_xmit ( tcp );
+}
+
+/**
+ * Deliver datagram as I/O buffer
+ *
+ * @v tcp TCP connection
+ * @v iobuf Datagram I/O buffer
+ * @v meta Data transfer metadata
+ * @ret rc Return status code
+ */
+static int tcp_xfer_deliver ( struct tcp_connection *tcp,
+ struct io_buffer *iobuf,
+ struct xfer_metadata *meta __unused ) {
+
+ /* Enqueue packet */
+ list_add_tail ( &iobuf->list, &tcp->tx_queue );
+
+ /* Each enqueued packet is a pending operation */
+ pending_get ( &tcp->pending_data );
+
+ /* Transmit data, if possible */
+ tcp_xmit ( tcp );
+
+ return 0;
+}
+
+/** TCP data transfer interface operations */
+static struct interface_operation tcp_xfer_operations[] = {
+ INTF_OP ( xfer_deliver, struct tcp_connection *, tcp_xfer_deliver ),
+ INTF_OP ( xfer_window, struct tcp_connection *, tcp_xfer_window ),
+ INTF_OP ( intf_close, struct tcp_connection *, tcp_xfer_close ),
+};
+
+/** TCP data transfer interface descriptor */
+static struct interface_descriptor tcp_xfer_desc =
+ INTF_DESC ( struct tcp_connection, xfer, tcp_xfer_operations );
+
+/***************************************************************************
+ *
+ * Openers
+ *
+ ***************************************************************************
+ */
+
+/** TCP IPv4 socket opener */
+struct socket_opener tcp_ipv4_socket_opener __socket_opener = {
+ .semantics = TCP_SOCK_STREAM,
+ .family = AF_INET,
+ .open = tcp_open,
+};
+
+/** TCP IPv6 socket opener */
+struct socket_opener tcp_ipv6_socket_opener __socket_opener = {
+ .semantics = TCP_SOCK_STREAM,
+ .family = AF_INET6,
+ .open = tcp_open,
+};
+
+/** Linkage hack */
+int tcp_sock_stream = TCP_SOCK_STREAM;
+
+/**
+ * Open TCP URI
+ *
+ * @v xfer Data transfer interface
+ * @v uri URI
+ * @ret rc Return status code
+ */
+static int tcp_open_uri ( struct interface *xfer, struct uri *uri ) {
+ struct sockaddr_tcpip peer;
+
+ /* Sanity check */
+ if ( ! uri->host )
+ return -EINVAL;
+
+ memset ( &peer, 0, sizeof ( peer ) );
+ peer.st_port = htons ( uri_port ( uri, 0 ) );
+ return xfer_open_named_socket ( xfer, SOCK_STREAM,
+ ( struct sockaddr * ) &peer,
+ uri->host, NULL );
+}
+
+/** TCP URI opener */
+struct uri_opener tcp_uri_opener __uri_opener = {
+ .scheme = "tcp",
+ .open = tcp_open_uri,
+};
+
Code Review / kvmfornfv.git / blobdiff