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TCP: Change how initial MSS is handled. From Max Holtzberg

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This commit is contained in:
Gregory Nutt 2013-10-17 09:45:38 -06:00
parent 69dac5c775
commit cbed482747
5 changed files with 72 additions and 71 deletions
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3
ChangeLog
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@ -5782,4 +5782,7 @@
checking for timeout. From Max Holtzberg (2013-10-17). checking for timeout. From Max Holtzberg (2013-10-17).
* net/net_sendfile.c: Correct paramter passed to netdev_txnotify() * net/net_sendfile.c: Correct paramter passed to netdev_txnotify()
from Max Holtzberg (2013-10-17). from Max Holtzberg (2013-10-17).
* include/nuttx/net/uip/uip-tcp.h, net/send.c, uip/uip_tcpconn.c, and
uip/uip_tcpinput.c: Change how the inital minimum MSS is calculated.
Max Holtzberg (2013-10-17).

30
include/nuttx/net/uip/uip-tcp.h
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@ -105,6 +105,24 @@
#define UIP_IPTCPH_LEN (UIP_TCPH_LEN + UIP_IPH_LEN) /* Size of IP + TCP header */ #define UIP_IPTCPH_LEN (UIP_TCPH_LEN + UIP_IPH_LEN) /* Size of IP + TCP header */
#define UIP_TCPIP_HLEN UIP_IPTCPH_LEN #define UIP_TCPIP_HLEN UIP_IPTCPH_LEN
/* Initial minimum MSS according to RFC 879
*
* There have been some assumptions made about using other than the
* default size for datagrams with some unfortunate results.
*
* HOSTS MUST NOT SEND DATAGRAMS LARGER THAN 576 OCTETS UNLESS THEY
* HAVE SPECIFIC KNOWLEDGE THAT THE DESTINATION HOST IS PREPARED TO
* ACCEPT LARGER DATAGRAMS.
*
* This is a long established rule.
*/
#if UIP_TCP_MSS > 576
# define UIP_TCP_INITIAL_MSS 576
#else
# define UIP_TCP_INITIAL_MSS UIP_TCP_MSS
#endif
/**************************************************************************** /****************************************************************************
* Public Type Definitions * Public Type Definitions
****************************************************************************/ ****************************************************************************/
@ -135,8 +153,6 @@ struct uip_conn
uint16_t mss; /* Current maximum segment size for the uint16_t mss; /* Current maximum segment size for the
* connection */ * connection */
uint16_t winsize; /* Current window size of the connection */ uint16_t winsize; /* Current window size of the connection */
uint16_t initialmss; /* Initial maximum segment size for the
* connection */
uint8_t crefs; /* Reference counts on this instance */ uint8_t crefs; /* Reference counts on this instance */
uint8_t sa; /* Retransmission time-out calculation state uint8_t sa; /* Retransmission time-out calculation state
* variable */ * variable */
@ -444,18 +460,8 @@ extern int uip_backlogdelete(FAR struct uip_conn *conn, FAR struct uip_conn *blc
(conn)->tcpstateflags &= ~UIP_STOPPED; \ (conn)->tcpstateflags &= ~UIP_STOPPED; \
} while(0) } while(0)
/* Get the initial maxium segment size (MSS) of the current
* connection.
*/
#define uip_initialmss(conn) ((conn)->initialmss)
/* Get the current maximum segment size that can be sent on the current /* Get the current maximum segment size that can be sent on the current
* connection. * connection.
*
* The current maxiumum segment size that can be sent on the connection is
* computed from the receiver's window and the MSS of the connection (which
* also is available by calling uip_initialmss()).
*/ */
#define uip_mss(conn) ((conn)->mss) #define uip_mss(conn) ((conn)->mss)

69
net/send.c
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@ -356,45 +356,52 @@ static uint16_t send_interrupt(FAR struct uip_driver_s *dev, FAR void *pvconn,
sndlen = uip_mss(conn); sndlen = uip_mss(conn);
} }
/* Set the sequence number for this packet. NOTE: uIP updates /* Check if we have "space" in the window */
* sndseq on recept of ACK *before* this function is called. In that
* case sndseq will point to the next unacknowledge byte (which might
* have already been sent). We will overwrite the value of sndseq
* here before the packet is sent.
*/
seqno = pstate->snd_sent + pstate->snd_isn; if ((pstate->snd_sent - pstate->snd_acked + sndlen) < conn->winsize)
nllvdbg("SEND: sndseq %08x->%08x\n", conn->sndseq, seqno); {
uip_tcpsetsequence(conn->sndseq, seqno);
/* Then set-up to send that amount of data. (this won't actually /* Set the sequence number for this packet. NOTE: uIP updates
* happen until the polling cycle completes). * sndseq on recept of ACK *before* this function is called. In that
*/ * case sndseq will point to the next unacknowledge byte (which might
* have already been sent). We will overwrite the value of sndseq
* here before the packet is sent.
*/
uip_send(dev, &pstate->snd_buffer[pstate->snd_sent], sndlen); seqno = pstate->snd_sent + pstate->snd_isn;
nllvdbg("SEND: sndseq %08x->%08x\n", conn->sndseq, seqno);
uip_tcpsetsequence(conn->sndseq, seqno);
/* Check if the destination IP address is in the ARP table. If not, /* Then set-up to send that amount of data. (this won't actually
* then the send won't actually make it out... it will be replaced with * happen until the polling cycle completes).
* an ARP request. */
*
* NOTE 1: This could be an expensive check if there are a lot of entries uip_send(dev, &pstate->snd_buffer[pstate->snd_sent], sndlen);
* in the ARP table. Hence, we only check on the first packet -- when
* snd_sent is zero. /* Check if the destination IP address is in the ARP table. If not,
* * then the send won't actually make it out... it will be replaced with
* NOTE 2: If we are actually harvesting IP addresses on incomming IP * an ARP request.
* packets, then this check should not be necessary; the MAC mapping *
* should already be in the ARP table. * NOTE 1: This could be an expensive check if there are a lot of entries
*/ * in the ARP table. Hence, we only check on the first packet -- when
* snd_sent is zero.
*
* NOTE 2: If we are actually harvesting IP addresses on incomming IP
* packets, then this check should not be necessary; the MAC mapping
* should already be in the ARP table.
*/
#if defined(CONFIG_NET_ETHERNET) && !defined(CONFIG_NET_ARP_IPIN) #if defined(CONFIG_NET_ETHERNET) && !defined(CONFIG_NET_ARP_IPIN)
if (pstate->snd_sent != 0 || uip_arp_find(conn->ripaddr) != NULL) if (pstate->snd_sent != 0 || uip_arp_find(conn->ripaddr) != NULL)
#endif #endif
{ {
/* Update the amount of data sent (but not necessarily ACKed) */ /* Update the amount of data sent (but not necessarily ACKed) */
pstate->snd_sent += sndlen; pstate->snd_sent += sndlen;
nllvdbg("SEND: acked=%d sent=%d buflen=%d\n", nllvdbg("SEND: acked=%d sent=%d buflen=%d\n",
pstate->snd_acked, pstate->snd_sent, pstate->snd_buflen); pstate->snd_acked, pstate->snd_sent, pstate->snd_buflen);
}
} }
} }

3
net/uip/uip_tcpconn.c
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@ -496,6 +496,7 @@ struct uip_conn *uip_tcpaccept(struct uip_tcpip_hdr *buf)
conn->nrtx = 0; conn->nrtx = 0;
conn->lport = buf->destport; conn->lport = buf->destport;
conn->rport = buf->srcport; conn->rport = buf->srcport;
conn->mss = UIP_TCP_INITIAL_MSS;
uip_ipaddr_copy(conn->ripaddr, uip_ip4addr_conv(buf->srcipaddr)); uip_ipaddr_copy(conn->ripaddr, uip_ip4addr_conv(buf->srcipaddr));
conn->tcpstateflags = UIP_SYN_RCVD; conn->tcpstateflags = UIP_SYN_RCVD;
@ -632,7 +633,7 @@ int uip_tcpconnect(struct uip_conn *conn, const struct sockaddr_in *addr)
conn->tcpstateflags = UIP_SYN_SENT; conn->tcpstateflags = UIP_SYN_SENT;
uip_tcpinitsequence(conn->sndseq); uip_tcpinitsequence(conn->sndseq);
conn->initialmss = conn->mss = UIP_TCP_MSS; conn->mss = UIP_TCP_INITIAL_MSS;
conn->unacked = 1; /* TCP length of the SYN is one. */ conn->unacked = 1; /* TCP length of the SYN is one. */
conn->nrtx = 0; conn->nrtx = 0;
conn->timer = 1; /* Send the SYN next time around. */ conn->timer = 1; /* Send the SYN next time around. */

38
net/uip/uip_tcpinput.c
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@ -2,7 +2,7 @@
* net/uip/uip_tcpinput.c * net/uip/uip_tcpinput.c
* Handling incoming TCP input * Handling incoming TCP input
* *
* Copyright (C) 2007-2012 Gregory Nutt. All rights reserved. * Copyright (C) 2007-2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org> * Author: Gregory Nutt <gnutt@nuttx.org>
* *
* Adapted for NuttX from logic in uIP which also has a BSD-like license: * Adapted for NuttX from logic in uIP which also has a BSD-like license:
@ -244,8 +244,7 @@ void uip_tcpinput(struct uip_driver_s *dev)
tmp16 = ((uint16_t)dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + i] << 8) | tmp16 = ((uint16_t)dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + i] << 8) |
(uint16_t)dev->d_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN + 3 + i]; (uint16_t)dev->d_buf[UIP_IPTCPH_LEN + UIP_LLH_LEN + 3 + i];
conn->initialmss = conn->mss = conn->mss = tmp16 > UIP_TCP_MSS ? UIP_TCP_MSS : tmp16;
tmp16 > UIP_TCP_MSS? UIP_TCP_MSS: tmp16;
/* And we are done processing options. */ /* And we are done processing options. */
@ -300,7 +299,7 @@ found:
/* Update the connection's window size */ /* Update the connection's window size */
conn->winsize = BUF->wnd[0] << 8 | BUF->wnd[1]; conn->winsize = ((uint16_t)pbuf->wnd[0] << 8) + (uint16_t)pbuf->wnd[1];
flags = 0; flags = 0;
@ -522,9 +521,7 @@ found:
tmp16 = tmp16 =
(dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + i] << 8) | (dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 2 + i] << 8) |
dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 3 + i]; dev->d_buf[UIP_TCPIP_HLEN + UIP_LLH_LEN + 3 + i];
conn->initialmss = conn->mss = tmp16 > UIP_TCP_MSS ? UIP_TCP_MSS : tmp16;
conn->mss =
tmp16 > UIP_TCP_MSS? UIP_TCP_MSS: tmp16;
/* And we are done processing options. */ /* And we are done processing options. */
@ -595,10 +592,17 @@ found:
if ((pbuf->flags & TCP_FIN) != 0 && (conn->tcpstateflags & UIP_STOPPED) == 0) if ((pbuf->flags & TCP_FIN) != 0 && (conn->tcpstateflags & UIP_STOPPED) == 0)
{ {
/* Needs to be investigated further.
* Windows often sends FIN packets together with the last ACK for
* the received data. So the socket layer has to get this ACK even
* if the connection is going to be closed.
*/
#if 0
if (conn->unacked > 0) if (conn->unacked > 0)
{ {
goto drop; goto drop;
} }
#endif
/* Update the sequence number and indicate that the connection has /* Update the sequence number and indicate that the connection has
* been closed. * been closed.
@ -663,26 +667,6 @@ found:
flags |= UIP_NEWDATA; flags |= UIP_NEWDATA;
} }
/* Check if the available buffer space advertised by the other end
* is smaller than the initial MSS for this connection. If so, we
* set the current MSS to the window size to ensure that the
* application does not send more data than the other end can
* handle.
*
* If the remote host advertises a zero window, we set the MSS to
* the initial MSS so that the application will send an entire MSS
* of data. This data will not be acknowledged by the receiver,
* and the application will retransmit it. This is called the
* "persistent timer" and uses the retransmission mechanim.
*/
tmp16 = ((uint16_t)pbuf->wnd[0] << 8) + (uint16_t)pbuf->wnd[1];
if (tmp16 > conn->initialmss || tmp16 == 0)
{
tmp16 = conn->initialmss;
}
conn->mss = tmp16;
/* If this packet constitutes an ACK for outstanding data (flagged /* If this packet constitutes an ACK for outstanding data (flagged
* by the UIP_ACKDATA flag), we should call the application since it * by the UIP_ACKDATA flag), we should call the application since it
* might want to send more data. If the incoming packet had data * might want to send more data. If the incoming packet had data