diff options
Diffstat (limited to 'nuttx/net/send.c')
| -rw-r--r-- | nuttx/net/send.c | 104 |
1 files changed, 103 insertions, 1 deletions
diff --git a/nuttx/net/send.c b/nuttx/net/send.c index 8a5154191..79dfef4ec 100644 --- a/nuttx/net/send.c +++ b/nuttx/net/send.c @@ -1,7 +1,7 @@ /**************************************************************************** * net/send.c * - * Copyright (C) 2007-2012 Gregory Nutt. All rights reserved. + * Copyright (C) 2007-2013 Gregory Nutt. All rights reserved. * Author: Gregory Nutt <gnutt@nuttx.org> * * Redistribution and use in source and binary forms, with or without @@ -42,7 +42,9 @@ #include <sys/types.h> #include <sys/socket.h> + #include <stdint.h> +#include <stdbool.h> #include <string.h> #include <errno.h> #include <debug.h> @@ -62,6 +64,10 @@ * Definitions ****************************************************************************/ +#if defined(CONFIG_NET_TCP_SPLIT) && !defined(CONFIG_NET_TCP_SPLIT_SIZE) +# define CONFIG_NET_TCP_SPLIT_SIZE 40 +#endif + #define TCPBUF ((struct uip_tcpip_hdr *)&dev->d_buf[UIP_LLH_LEN]) /**************************************************************************** @@ -85,6 +91,9 @@ struct send_s #if defined(CONFIG_NET_SOCKOPTS) && !defined(CONFIG_DISABLE_CLOCK) uint32_t snd_time; /* last send time for determining timeout */ #endif +#if defined(CONFIG_NET_TCP_SPLIT) + bool snd_odd; /* True: Odd packet in pair transaction */ +#endif }; /**************************************************************************** @@ -200,6 +209,14 @@ static uint16_t send_interrupt(struct uip_driver_s *dev, void *pvconn, pstate->snd_sent = pstate->snd_acked; +#if defined(CONFIG_NET_TCP_SPLIT) + /* Reset the the even/odd indicator to even since we need to + * retransmit. + */ + + pstate->snd_odd = false; +#endif + /* Fall through to re-send data from the last that was ACKed */ } @@ -210,6 +227,8 @@ static uint16_t send_interrupt(struct uip_driver_s *dev, void *pvconn, /* Report not connected */ nllvdbg("Lost connection\n"); + + net_lostconnection(pstate->snd_sock, flags); pstate->snd_sent = -ENOTCONN; goto end_wait; } @@ -242,6 +261,89 @@ static uint16_t send_interrupt(struct uip_driver_s *dev, void *pvconn, /* Get the amount of data that we can send in the next packet */ uint32_t sndlen = pstate->snd_buflen - pstate->snd_sent; + + +#if defined(CONFIG_NET_TCP_SPLIT) + + /* RFC 1122 states that a host may delay ACKing for up to 500ms but + * must respond to every second segment). This logic here will trick + * the RFC 1122 recipient into responding sooner. This logic will be + * activated if: + * + * 1. An even number of packets has been send (where zero is an even + * number), + * 2. There is more data be sent (more than or equal to + * CONFIG_NET_TCP_SPLIT_SIZE), but + * 3. Not enough data for two packets. + * + * Then we will split the remaining, single packet into two partial + * packets. This will stimulate the RFC 1122 peer to ACK sooner. + * + * Don't try to split very small packets (less than CONFIG_NET_TCP_SPLIT_SIZE). + * Only the first even packet and the last odd packets could have + * sndlen less than CONFIG_NET_TCP_SPLIT_SIZE. The value of sndlen on + * the last even packet is guaranteed to be at least MSS/2 by the + * logic below. + */ + + if (sndlen >= CONFIG_NET_TCP_SPLIT_SIZE) + { + /* sndlen is the number of bytes remaining to be sent. + * uip_mss(conn) will return the number of bytes that can sent + * in one packet. The difference, then, is the number of bytes + * that would be sent in the next packet after this one. + */ + + int32_t next_sndlen = sndlen - uip_mss(conn); + + /* Is this the even packet in the packet pair transaction? */ + + if (!pstate->snd_odd) + { + /* next_sndlen <= 0 means that the entire remaining data + * could fit into this single packet. This is condition + * in which we must do the split. + */ + + if (next_sndlen <= 0) + { + /* Split so that there will be an odd packet. Here + * we know that 0 < sndlen <= MSS + */ + + sndlen = (sndlen / 2) + 1; + } + } + + /* No... this is the odd packet in the packet pair transaction */ + + else + { + /* Will there be another (even) packet afer this one? + * (next_sndlen > 0) Will the split conidition occur on that + * next, even packet? ((next_sndlen - uip_mss(conn)) < 0) If + * so, then perform the split now to avoid the case where the + * byte count is less than CONFIG_NET_TCP_SPLIT_SIZE on the + * next pair. + */ + + if (next_sndlen > 0 && (next_sndlen - uip_mss(conn)) < 0) + { + /* Here, we know that sndlen must be MSS < sndlen <= 2*MSS + * and so (sndlen / 2) is <= MSS. + */ + + sndlen /= 2; + } + } + } + + /* Toggle the even/odd indicator */ + + pstate->snd_odd ^= true; + +#endif /* CONFIG_NET_TCP_SPLIT */ + if (sndlen > uip_mss(conn)) { sndlen = uip_mss(conn); |