1300 lines
31 KiB
C
1300 lines
31 KiB
C
//=====================================================================
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//
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// KCP - A Better ARQ Protocol Implementation
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// skywind3000 (at) gmail.com, 2010-2011
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//
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// Features:
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// + Average RTT reduce 30% - 40% vs traditional ARQ like tcp.
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// + Maximum RTT reduce three times vs tcp.
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// + Lightweight, distributed as a single source file.
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//
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//=====================================================================
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#include "ikcp.h"
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#include <stddef.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdarg.h>
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#include <stdio.h>
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//=====================================================================
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// KCP BASIC
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//=====================================================================
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const IUINT32 IKCP_RTO_NDL = 30; // no delay min rto
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const IUINT32 IKCP_RTO_MIN = 100; // normal min rto
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const IUINT32 IKCP_RTO_DEF = 200;
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const IUINT32 IKCP_RTO_MAX = 60000;
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const IUINT32 IKCP_CMD_PUSH = 81; // cmd: push data
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const IUINT32 IKCP_CMD_ACK = 82; // cmd: ack
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const IUINT32 IKCP_CMD_WASK = 83; // cmd: window probe (ask)
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const IUINT32 IKCP_CMD_WINS = 84; // cmd: window size (tell)
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const IUINT32 IKCP_ASK_SEND = 1; // need to send IKCP_CMD_WASK
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const IUINT32 IKCP_ASK_TELL = 2; // need to send IKCP_CMD_WINS
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const IUINT32 IKCP_WND_SND = 32;
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const IUINT32 IKCP_WND_RCV = 128; // must >= max fragment size
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const IUINT32 IKCP_MTU_DEF = 1400;
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const IUINT32 IKCP_ACK_FAST = 3;
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const IUINT32 IKCP_INTERVAL = 100;
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const IUINT32 IKCP_OVERHEAD = 24;
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const IUINT32 IKCP_DEADLINK = 20;
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const IUINT32 IKCP_THRESH_INIT = 2;
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const IUINT32 IKCP_THRESH_MIN = 2;
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const IUINT32 IKCP_PROBE_INIT = 7000; // 7 secs to probe window size
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const IUINT32 IKCP_PROBE_LIMIT = 120000; // up to 120 secs to probe window
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const IUINT32 IKCP_FASTACK_LIMIT = 5; // max times to trigger fastack
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//---------------------------------------------------------------------
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// encode / decode
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//---------------------------------------------------------------------
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/* encode 8 bits unsigned int */
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static inline char *ikcp_encode8u(char *p, unsigned char c)
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{
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*(unsigned char*)p++ = c;
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return p;
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}
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/* decode 8 bits unsigned int */
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static inline const char *ikcp_decode8u(const char *p, unsigned char *c)
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{
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*c = *(unsigned char*)p++;
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return p;
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}
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/* encode 16 bits unsigned int (lsb) */
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static inline char *ikcp_encode16u(char *p, unsigned short w)
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{
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#if IWORDS_BIG_ENDIAN || IWORDS_MUST_ALIGN
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*(unsigned char*)(p + 0) = (w & 255);
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*(unsigned char*)(p + 1) = (w >> 8);
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#else
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memcpy(p, &w, 2);
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#endif
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p += 2;
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return p;
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}
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/* decode 16 bits unsigned int (lsb) */
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static inline const char *ikcp_decode16u(const char *p, unsigned short *w)
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{
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#if IWORDS_BIG_ENDIAN || IWORDS_MUST_ALIGN
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*w = *(const unsigned char*)(p + 1);
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*w = *(const unsigned char*)(p + 0) + (*w << 8);
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#else
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memcpy(w, p, 2);
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#endif
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p += 2;
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return p;
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}
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/* encode 32 bits unsigned int (lsb) */
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static inline char *ikcp_encode32u(char *p, IUINT32 l)
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{
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#if IWORDS_BIG_ENDIAN || IWORDS_MUST_ALIGN
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*(unsigned char*)(p + 0) = (unsigned char)((l >> 0) & 0xff);
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*(unsigned char*)(p + 1) = (unsigned char)((l >> 8) & 0xff);
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*(unsigned char*)(p + 2) = (unsigned char)((l >> 16) & 0xff);
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*(unsigned char*)(p + 3) = (unsigned char)((l >> 24) & 0xff);
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#else
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memcpy(p, &l, 4);
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#endif
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p += 4;
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return p;
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}
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/* decode 32 bits unsigned int (lsb) */
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static inline const char *ikcp_decode32u(const char *p, IUINT32 *l)
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{
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#if IWORDS_BIG_ENDIAN || IWORDS_MUST_ALIGN
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*l = *(const unsigned char*)(p + 3);
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*l = *(const unsigned char*)(p + 2) + (*l << 8);
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*l = *(const unsigned char*)(p + 1) + (*l << 8);
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*l = *(const unsigned char*)(p + 0) + (*l << 8);
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#else
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memcpy(l, p, 4);
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#endif
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p += 4;
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return p;
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}
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static inline IUINT32 _imin_(IUINT32 a, IUINT32 b) {
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return a <= b ? a : b;
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}
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static inline IUINT32 _imax_(IUINT32 a, IUINT32 b) {
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return a >= b ? a : b;
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}
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static inline IUINT32 _ibound_(IUINT32 lower, IUINT32 middle, IUINT32 upper)
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{
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return _imin_(_imax_(lower, middle), upper);
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}
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static inline long _itimediff(IUINT32 later, IUINT32 earlier)
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{
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return ((IINT32)(later - earlier));
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}
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//---------------------------------------------------------------------
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// manage segment
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//---------------------------------------------------------------------
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typedef struct IKCPSEG IKCPSEG;
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static void* (*ikcp_malloc_hook)(size_t) = NULL;
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static void (*ikcp_free_hook)(void *) = NULL;
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// internal malloc
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static void* ikcp_malloc(size_t size) {
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if (ikcp_malloc_hook)
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return ikcp_malloc_hook(size);
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return malloc(size);
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}
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// internal free
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static void ikcp_free(void *ptr) {
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if (ikcp_free_hook) {
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ikcp_free_hook(ptr);
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} else {
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free(ptr);
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}
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}
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// redefine allocator
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void ikcp_allocator(void* (*new_malloc)(size_t), void (*new_free)(void*))
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{
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ikcp_malloc_hook = new_malloc;
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ikcp_free_hook = new_free;
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}
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// allocate a new kcp segment
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static IKCPSEG* ikcp_segment_new(ikcpcb *kcp, int size)
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{
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return (IKCPSEG*)ikcp_malloc(sizeof(IKCPSEG) + size);
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}
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// delete a segment
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static void ikcp_segment_delete(ikcpcb *kcp, IKCPSEG *seg)
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{
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ikcp_free(seg);
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}
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// write log
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void ikcp_log(ikcpcb *kcp, int mask, const char *fmt, ...)
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{
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char buffer[1024];
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va_list argptr;
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if ((mask & kcp->logmask) == 0 || kcp->writelog == 0) return;
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va_start(argptr, fmt);
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vsprintf(buffer, fmt, argptr);
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va_end(argptr);
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kcp->writelog(buffer, kcp, kcp->user);
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}
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// check log mask
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static int ikcp_canlog(const ikcpcb *kcp, int mask)
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{
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if ((mask & kcp->logmask) == 0 || kcp->writelog == NULL) return 0;
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return 1;
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}
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// output segment
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static int ikcp_output(ikcpcb *kcp, const void *data, int size)
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{
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assert(kcp);
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assert(kcp->output);
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if (ikcp_canlog(kcp, IKCP_LOG_OUTPUT)) {
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ikcp_log(kcp, IKCP_LOG_OUTPUT, "[RO] %ld bytes", (long)size);
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}
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if (size == 0) return 0;
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return kcp->output((const char*)data, size, kcp, kcp->user);
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}
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// output queue
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void ikcp_qprint(const char *name, const struct IQUEUEHEAD *head)
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{
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#if 0
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const struct IQUEUEHEAD *p;
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printf("<%s>: [", name);
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for (p = head->next; p != head; p = p->next) {
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const IKCPSEG *seg = iqueue_entry(p, const IKCPSEG, node);
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printf("(%lu %d)", (unsigned long)seg->sn, (int)(seg->ts % 10000));
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if (p->next != head) printf(",");
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}
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printf("]\n");
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#endif
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}
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//---------------------------------------------------------------------
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// create a new kcpcb
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//---------------------------------------------------------------------
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ikcpcb* ikcp_create(IUINT32 conv, void *user)
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{
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ikcpcb *kcp = (ikcpcb*)ikcp_malloc(sizeof(struct IKCPCB));
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if (kcp == NULL) return NULL;
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kcp->conv = conv;
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kcp->user = user;
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kcp->snd_una = 0;
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kcp->snd_nxt = 0;
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kcp->rcv_nxt = 0;
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kcp->ts_recent = 0;
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kcp->ts_lastack = 0;
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kcp->ts_probe = 0;
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kcp->probe_wait = 0;
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kcp->snd_wnd = IKCP_WND_SND;
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kcp->rcv_wnd = IKCP_WND_RCV;
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kcp->rmt_wnd = IKCP_WND_RCV;
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kcp->cwnd = 0;
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kcp->incr = 0;
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kcp->probe = 0;
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kcp->mtu = IKCP_MTU_DEF;
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kcp->mss = kcp->mtu - IKCP_OVERHEAD;
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kcp->stream = 0;
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kcp->buffer = (char*)ikcp_malloc((kcp->mtu + IKCP_OVERHEAD) * 3);
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if (kcp->buffer == NULL) {
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ikcp_free(kcp);
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return NULL;
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}
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iqueue_init(&kcp->snd_queue);
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iqueue_init(&kcp->rcv_queue);
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iqueue_init(&kcp->snd_buf);
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iqueue_init(&kcp->rcv_buf);
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kcp->nrcv_buf = 0;
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kcp->nsnd_buf = 0;
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kcp->nrcv_que = 0;
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kcp->nsnd_que = 0;
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kcp->state = 0;
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kcp->acklist = NULL;
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kcp->ackblock = 0;
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kcp->ackcount = 0;
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kcp->rx_srtt = 0;
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kcp->rx_rttval = 0;
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kcp->rx_rto = IKCP_RTO_DEF;
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kcp->rx_minrto = IKCP_RTO_MIN;
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kcp->current = 0;
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kcp->interval = IKCP_INTERVAL;
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kcp->ts_flush = IKCP_INTERVAL;
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kcp->nodelay = 0;
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kcp->updated = 0;
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kcp->logmask = 0;
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kcp->ssthresh = IKCP_THRESH_INIT;
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kcp->fastresend = 0;
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kcp->fastlimit = IKCP_FASTACK_LIMIT;
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kcp->nocwnd = 0;
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kcp->xmit = 0;
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kcp->dead_link = IKCP_DEADLINK;
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kcp->output = NULL;
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kcp->writelog = NULL;
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return kcp;
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}
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//---------------------------------------------------------------------
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// release a new kcpcb
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//---------------------------------------------------------------------
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void ikcp_release(ikcpcb *kcp)
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{
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assert(kcp);
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if (kcp) {
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IKCPSEG *seg;
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while (!iqueue_is_empty(&kcp->snd_buf)) {
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seg = iqueue_entry(kcp->snd_buf.next, IKCPSEG, node);
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iqueue_del(&seg->node);
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ikcp_segment_delete(kcp, seg);
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}
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while (!iqueue_is_empty(&kcp->rcv_buf)) {
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seg = iqueue_entry(kcp->rcv_buf.next, IKCPSEG, node);
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iqueue_del(&seg->node);
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ikcp_segment_delete(kcp, seg);
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}
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while (!iqueue_is_empty(&kcp->snd_queue)) {
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seg = iqueue_entry(kcp->snd_queue.next, IKCPSEG, node);
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iqueue_del(&seg->node);
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ikcp_segment_delete(kcp, seg);
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}
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while (!iqueue_is_empty(&kcp->rcv_queue)) {
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seg = iqueue_entry(kcp->rcv_queue.next, IKCPSEG, node);
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iqueue_del(&seg->node);
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ikcp_segment_delete(kcp, seg);
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}
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if (kcp->buffer) {
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ikcp_free(kcp->buffer);
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}
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if (kcp->acklist) {
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ikcp_free(kcp->acklist);
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}
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kcp->nrcv_buf = 0;
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kcp->nsnd_buf = 0;
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kcp->nrcv_que = 0;
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kcp->nsnd_que = 0;
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kcp->ackcount = 0;
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kcp->buffer = NULL;
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kcp->acklist = NULL;
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ikcp_free(kcp);
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}
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}
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//---------------------------------------------------------------------
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// set output callback, which will be invoked by kcp
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//---------------------------------------------------------------------
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void ikcp_setoutput(ikcpcb *kcp, int (*output)(const char *buf, int len,
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ikcpcb *kcp, void *user))
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{
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kcp->output = output;
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}
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//---------------------------------------------------------------------
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// user/upper level recv: returns size, returns below zero for EAGAIN
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//---------------------------------------------------------------------
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int ikcp_recv(ikcpcb *kcp, char *buffer, int len)
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{
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struct IQUEUEHEAD *p;
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int ispeek = (len < 0)? 1 : 0;
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int peeksize;
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int recover = 0;
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IKCPSEG *seg;
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assert(kcp);
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if (iqueue_is_empty(&kcp->rcv_queue))
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return -1;
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if (len < 0) len = -len;
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peeksize = ikcp_peeksize(kcp);
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if (peeksize < 0)
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return -2;
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if (peeksize > len)
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return -3;
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if (kcp->nrcv_que >= kcp->rcv_wnd)
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recover = 1;
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// merge fragment
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for (len = 0, p = kcp->rcv_queue.next; p != &kcp->rcv_queue; ) {
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int fragment;
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seg = iqueue_entry(p, IKCPSEG, node);
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p = p->next;
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if (buffer) {
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memcpy(buffer, seg->data, seg->len);
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buffer += seg->len;
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}
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len += seg->len;
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fragment = seg->frg;
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if (ikcp_canlog(kcp, IKCP_LOG_RECV)) {
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ikcp_log(kcp, IKCP_LOG_RECV, "recv sn=%lu", (unsigned long)seg->sn);
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}
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if (ispeek == 0) {
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iqueue_del(&seg->node);
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ikcp_segment_delete(kcp, seg);
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kcp->nrcv_que--;
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}
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if (fragment == 0)
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break;
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}
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assert(len == peeksize);
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// move available data from rcv_buf -> rcv_queue
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while (! iqueue_is_empty(&kcp->rcv_buf)) {
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seg = iqueue_entry(kcp->rcv_buf.next, IKCPSEG, node);
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if (seg->sn == kcp->rcv_nxt && kcp->nrcv_que < kcp->rcv_wnd) {
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iqueue_del(&seg->node);
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kcp->nrcv_buf--;
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iqueue_add_tail(&seg->node, &kcp->rcv_queue);
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kcp->nrcv_que++;
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kcp->rcv_nxt++;
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} else {
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break;
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}
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}
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// fast recover
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if (kcp->nrcv_que < kcp->rcv_wnd && recover) {
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// ready to send back IKCP_CMD_WINS in ikcp_flush
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// tell remote my window size
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kcp->probe |= IKCP_ASK_TELL;
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}
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return len;
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}
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//---------------------------------------------------------------------
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// peek data size
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//---------------------------------------------------------------------
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int ikcp_peeksize(const ikcpcb *kcp)
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{
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struct IQUEUEHEAD *p;
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IKCPSEG *seg;
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int length = 0;
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assert(kcp);
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if (iqueue_is_empty(&kcp->rcv_queue)) return -1;
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seg = iqueue_entry(kcp->rcv_queue.next, IKCPSEG, node);
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if (seg->frg == 0) return seg->len;
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if (kcp->nrcv_que < seg->frg + 1) return -1;
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for (p = kcp->rcv_queue.next; p != &kcp->rcv_queue; p = p->next) {
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seg = iqueue_entry(p, IKCPSEG, node);
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length += seg->len;
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if (seg->frg == 0) break;
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}
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return length;
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}
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//---------------------------------------------------------------------
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// user/upper level send, returns below zero for error
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//---------------------------------------------------------------------
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int ikcp_send(ikcpcb *kcp, const char *buffer, int len)
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{
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IKCPSEG *seg;
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int count, i;
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assert(kcp->mss > 0);
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if (len < 0) return -1;
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// append to previous segment in streaming mode (if possible)
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if (kcp->stream != 0) {
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if (!iqueue_is_empty(&kcp->snd_queue)) {
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IKCPSEG *old = iqueue_entry(kcp->snd_queue.prev, IKCPSEG, node);
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if (old->len < kcp->mss) {
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int capacity = kcp->mss - old->len;
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int extend = (len < capacity)? len : capacity;
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seg = ikcp_segment_new(kcp, old->len + extend);
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assert(seg);
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if (seg == NULL) {
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return -2;
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}
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iqueue_add_tail(&seg->node, &kcp->snd_queue);
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memcpy(seg->data, old->data, old->len);
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if (buffer) {
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memcpy(seg->data + old->len, buffer, extend);
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buffer += extend;
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}
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seg->len = old->len + extend;
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seg->frg = 0;
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len -= extend;
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iqueue_del_init(&old->node);
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ikcp_segment_delete(kcp, old);
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}
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}
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if (len <= 0) {
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
if (len <= (int)kcp->mss) count = 1;
|
|
else count = (len + kcp->mss - 1) / kcp->mss;
|
|
|
|
if (count >= (int)IKCP_WND_RCV) return -2;
|
|
|
|
if (count == 0) count = 1;
|
|
|
|
// fragment
|
|
for (i = 0; i < count; i++) {
|
|
int size = len > (int)kcp->mss ? (int)kcp->mss : len;
|
|
seg = ikcp_segment_new(kcp, size);
|
|
assert(seg);
|
|
if (seg == NULL) {
|
|
return -2;
|
|
}
|
|
if (buffer && len > 0) {
|
|
memcpy(seg->data, buffer, size);
|
|
}
|
|
seg->len = size;
|
|
seg->frg = (kcp->stream == 0)? (count - i - 1) : 0;
|
|
iqueue_init(&seg->node);
|
|
iqueue_add_tail(&seg->node, &kcp->snd_queue);
|
|
kcp->nsnd_que++;
|
|
if (buffer) {
|
|
buffer += size;
|
|
}
|
|
len -= size;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
//---------------------------------------------------------------------
|
|
// parse ack
|
|
//---------------------------------------------------------------------
|
|
static void ikcp_update_ack(ikcpcb *kcp, IINT32 rtt)
|
|
{
|
|
IINT32 rto = 0;
|
|
if (kcp->rx_srtt == 0) {
|
|
kcp->rx_srtt = rtt;
|
|
kcp->rx_rttval = rtt / 2;
|
|
} else {
|
|
long delta = rtt - kcp->rx_srtt;
|
|
if (delta < 0) delta = -delta;
|
|
kcp->rx_rttval = (3 * kcp->rx_rttval + delta) / 4;
|
|
kcp->rx_srtt = (7 * kcp->rx_srtt + rtt) / 8;
|
|
if (kcp->rx_srtt < 1) kcp->rx_srtt = 1;
|
|
}
|
|
rto = kcp->rx_srtt + _imax_(kcp->interval, 4 * kcp->rx_rttval);
|
|
kcp->rx_rto = _ibound_(kcp->rx_minrto, rto, IKCP_RTO_MAX);
|
|
}
|
|
|
|
static void ikcp_shrink_buf(ikcpcb *kcp)
|
|
{
|
|
struct IQUEUEHEAD *p = kcp->snd_buf.next;
|
|
if (p != &kcp->snd_buf) {
|
|
IKCPSEG *seg = iqueue_entry(p, IKCPSEG, node);
|
|
kcp->snd_una = seg->sn;
|
|
} else {
|
|
kcp->snd_una = kcp->snd_nxt;
|
|
}
|
|
}
|
|
|
|
static void ikcp_parse_ack(ikcpcb *kcp, IUINT32 sn)
|
|
{
|
|
struct IQUEUEHEAD *p, *next;
|
|
|
|
if (_itimediff(sn, kcp->snd_una) < 0 || _itimediff(sn, kcp->snd_nxt) >= 0)
|
|
return;
|
|
|
|
for (p = kcp->snd_buf.next; p != &kcp->snd_buf; p = next) {
|
|
IKCPSEG *seg = iqueue_entry(p, IKCPSEG, node);
|
|
next = p->next;
|
|
if (sn == seg->sn) {
|
|
iqueue_del(p);
|
|
ikcp_segment_delete(kcp, seg);
|
|
kcp->nsnd_buf--;
|
|
break;
|
|
}
|
|
if (_itimediff(sn, seg->sn) < 0) {
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void ikcp_parse_una(ikcpcb *kcp, IUINT32 una)
|
|
{
|
|
struct IQUEUEHEAD *p, *next;
|
|
for (p = kcp->snd_buf.next; p != &kcp->snd_buf; p = next) {
|
|
IKCPSEG *seg = iqueue_entry(p, IKCPSEG, node);
|
|
next = p->next;
|
|
if (_itimediff(una, seg->sn) > 0) {
|
|
iqueue_del(p);
|
|
ikcp_segment_delete(kcp, seg);
|
|
kcp->nsnd_buf--;
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void ikcp_parse_fastack(ikcpcb *kcp, IUINT32 sn, IUINT32 ts)
|
|
{
|
|
struct IQUEUEHEAD *p, *next;
|
|
|
|
if (_itimediff(sn, kcp->snd_una) < 0 || _itimediff(sn, kcp->snd_nxt) >= 0)
|
|
return;
|
|
|
|
for (p = kcp->snd_buf.next; p != &kcp->snd_buf; p = next) {
|
|
IKCPSEG *seg = iqueue_entry(p, IKCPSEG, node);
|
|
next = p->next;
|
|
if (_itimediff(sn, seg->sn) < 0) {
|
|
break;
|
|
}
|
|
else if (sn != seg->sn) {
|
|
#ifndef IKCP_FASTACK_CONSERVE
|
|
seg->fastack++;
|
|
#else
|
|
if (_itimediff(ts, seg->ts) >= 0)
|
|
seg->fastack++;
|
|
#endif
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
//---------------------------------------------------------------------
|
|
// ack append
|
|
//---------------------------------------------------------------------
|
|
static void ikcp_ack_push(ikcpcb *kcp, IUINT32 sn, IUINT32 ts)
|
|
{
|
|
size_t newsize = kcp->ackcount + 1;
|
|
IUINT32 *ptr;
|
|
|
|
if (newsize > kcp->ackblock) {
|
|
IUINT32 *acklist;
|
|
size_t newblock;
|
|
|
|
for (newblock = 8; newblock < newsize; newblock <<= 1);
|
|
acklist = (IUINT32*)ikcp_malloc(newblock * sizeof(IUINT32) * 2);
|
|
|
|
if (acklist == NULL) {
|
|
assert(acklist != NULL);
|
|
abort();
|
|
}
|
|
|
|
if (kcp->acklist != NULL) {
|
|
size_t x;
|
|
for (x = 0; x < kcp->ackcount; x++) {
|
|
acklist[x * 2 + 0] = kcp->acklist[x * 2 + 0];
|
|
acklist[x * 2 + 1] = kcp->acklist[x * 2 + 1];
|
|
}
|
|
ikcp_free(kcp->acklist);
|
|
}
|
|
|
|
kcp->acklist = acklist;
|
|
kcp->ackblock = newblock;
|
|
}
|
|
|
|
ptr = &kcp->acklist[kcp->ackcount * 2];
|
|
ptr[0] = sn;
|
|
ptr[1] = ts;
|
|
kcp->ackcount++;
|
|
}
|
|
|
|
static void ikcp_ack_get(const ikcpcb *kcp, int p, IUINT32 *sn, IUINT32 *ts)
|
|
{
|
|
if (sn) sn[0] = kcp->acklist[p * 2 + 0];
|
|
if (ts) ts[0] = kcp->acklist[p * 2 + 1];
|
|
}
|
|
|
|
|
|
//---------------------------------------------------------------------
|
|
// parse data
|
|
//---------------------------------------------------------------------
|
|
void ikcp_parse_data(ikcpcb *kcp, IKCPSEG *newseg)
|
|
{
|
|
struct IQUEUEHEAD *p, *prev;
|
|
IUINT32 sn = newseg->sn;
|
|
int repeat = 0;
|
|
|
|
if (_itimediff(sn, kcp->rcv_nxt + kcp->rcv_wnd) >= 0 ||
|
|
_itimediff(sn, kcp->rcv_nxt) < 0) {
|
|
ikcp_segment_delete(kcp, newseg);
|
|
return;
|
|
}
|
|
|
|
for (p = kcp->rcv_buf.prev; p != &kcp->rcv_buf; p = prev) {
|
|
IKCPSEG *seg = iqueue_entry(p, IKCPSEG, node);
|
|
prev = p->prev;
|
|
if (seg->sn == sn) {
|
|
repeat = 1;
|
|
break;
|
|
}
|
|
if (_itimediff(sn, seg->sn) > 0) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (repeat == 0) {
|
|
iqueue_init(&newseg->node);
|
|
iqueue_add(&newseg->node, p);
|
|
kcp->nrcv_buf++;
|
|
} else {
|
|
ikcp_segment_delete(kcp, newseg);
|
|
}
|
|
|
|
#if 0
|
|
ikcp_qprint("rcvbuf", &kcp->rcv_buf);
|
|
printf("rcv_nxt=%lu\n", kcp->rcv_nxt);
|
|
#endif
|
|
|
|
// move available data from rcv_buf -> rcv_queue
|
|
while (! iqueue_is_empty(&kcp->rcv_buf)) {
|
|
IKCPSEG *seg = iqueue_entry(kcp->rcv_buf.next, IKCPSEG, node);
|
|
if (seg->sn == kcp->rcv_nxt && kcp->nrcv_que < kcp->rcv_wnd) {
|
|
iqueue_del(&seg->node);
|
|
kcp->nrcv_buf--;
|
|
iqueue_add_tail(&seg->node, &kcp->rcv_queue);
|
|
kcp->nrcv_que++;
|
|
kcp->rcv_nxt++;
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
|
|
#if 0
|
|
ikcp_qprint("queue", &kcp->rcv_queue);
|
|
printf("rcv_nxt=%lu\n", kcp->rcv_nxt);
|
|
#endif
|
|
|
|
#if 1
|
|
// printf("snd(buf=%d, queue=%d)\n", kcp->nsnd_buf, kcp->nsnd_que);
|
|
// printf("rcv(buf=%d, queue=%d)\n", kcp->nrcv_buf, kcp->nrcv_que);
|
|
#endif
|
|
}
|
|
|
|
|
|
//---------------------------------------------------------------------
|
|
// input data
|
|
//---------------------------------------------------------------------
|
|
int ikcp_input(ikcpcb *kcp, const char *data, long size)
|
|
{
|
|
IUINT32 prev_una = kcp->snd_una;
|
|
IUINT32 maxack = 0, latest_ts = 0;
|
|
int flag = 0;
|
|
|
|
if (ikcp_canlog(kcp, IKCP_LOG_INPUT)) {
|
|
ikcp_log(kcp, IKCP_LOG_INPUT, "[RI] %d bytes", (int)size);
|
|
}
|
|
|
|
if (data == NULL || (int)size < (int)IKCP_OVERHEAD) return -1;
|
|
|
|
while (1) {
|
|
IUINT32 ts, sn, len, una, conv;
|
|
IUINT16 wnd;
|
|
IUINT8 cmd, frg;
|
|
IKCPSEG *seg;
|
|
|
|
if (size < (int)IKCP_OVERHEAD) break;
|
|
|
|
data = ikcp_decode32u(data, &conv);
|
|
if (conv != kcp->conv) return -1;
|
|
|
|
data = ikcp_decode8u(data, &cmd);
|
|
data = ikcp_decode8u(data, &frg);
|
|
data = ikcp_decode16u(data, &wnd);
|
|
data = ikcp_decode32u(data, &ts);
|
|
data = ikcp_decode32u(data, &sn);
|
|
data = ikcp_decode32u(data, &una);
|
|
data = ikcp_decode32u(data, &len);
|
|
|
|
size -= IKCP_OVERHEAD;
|
|
|
|
if ((long)size < (long)len || (int)len < 0) return -2;
|
|
|
|
if (cmd != IKCP_CMD_PUSH && cmd != IKCP_CMD_ACK &&
|
|
cmd != IKCP_CMD_WASK && cmd != IKCP_CMD_WINS)
|
|
return -3;
|
|
|
|
kcp->rmt_wnd = wnd;
|
|
ikcp_parse_una(kcp, una);
|
|
ikcp_shrink_buf(kcp);
|
|
|
|
if (cmd == IKCP_CMD_ACK) {
|
|
if (_itimediff(kcp->current, ts) >= 0) {
|
|
ikcp_update_ack(kcp, _itimediff(kcp->current, ts));
|
|
}
|
|
ikcp_parse_ack(kcp, sn);
|
|
ikcp_shrink_buf(kcp);
|
|
if (flag == 0) {
|
|
flag = 1;
|
|
maxack = sn;
|
|
latest_ts = ts;
|
|
} else {
|
|
if (_itimediff(sn, maxack) > 0) {
|
|
#ifndef IKCP_FASTACK_CONSERVE
|
|
maxack = sn;
|
|
latest_ts = ts;
|
|
#else
|
|
if (_itimediff(ts, latest_ts) > 0) {
|
|
maxack = sn;
|
|
latest_ts = ts;
|
|
}
|
|
#endif
|
|
}
|
|
}
|
|
if (ikcp_canlog(kcp, IKCP_LOG_IN_ACK)) {
|
|
ikcp_log(kcp, IKCP_LOG_IN_ACK,
|
|
"input ack: sn=%lu rtt=%ld rto=%ld", (unsigned long)sn,
|
|
(long)_itimediff(kcp->current, ts),
|
|
(long)kcp->rx_rto);
|
|
}
|
|
}
|
|
else if (cmd == IKCP_CMD_PUSH) {
|
|
if (ikcp_canlog(kcp, IKCP_LOG_IN_DATA)) {
|
|
ikcp_log(kcp, IKCP_LOG_IN_DATA,
|
|
"input psh: sn=%lu ts=%lu", (unsigned long)sn, (unsigned long)ts);
|
|
}
|
|
if (_itimediff(sn, kcp->rcv_nxt + kcp->rcv_wnd) < 0) {
|
|
ikcp_ack_push(kcp, sn, ts);
|
|
if (_itimediff(sn, kcp->rcv_nxt) >= 0) {
|
|
seg = ikcp_segment_new(kcp, len);
|
|
seg->conv = conv;
|
|
seg->cmd = cmd;
|
|
seg->frg = frg;
|
|
seg->wnd = wnd;
|
|
seg->ts = ts;
|
|
seg->sn = sn;
|
|
seg->una = una;
|
|
seg->len = len;
|
|
|
|
if (len > 0) {
|
|
memcpy(seg->data, data, len);
|
|
}
|
|
|
|
ikcp_parse_data(kcp, seg);
|
|
}
|
|
}
|
|
}
|
|
else if (cmd == IKCP_CMD_WASK) {
|
|
// ready to send back IKCP_CMD_WINS in ikcp_flush
|
|
// tell remote my window size
|
|
kcp->probe |= IKCP_ASK_TELL;
|
|
if (ikcp_canlog(kcp, IKCP_LOG_IN_PROBE)) {
|
|
ikcp_log(kcp, IKCP_LOG_IN_PROBE, "input probe");
|
|
}
|
|
}
|
|
else if (cmd == IKCP_CMD_WINS) {
|
|
// do nothing
|
|
if (ikcp_canlog(kcp, IKCP_LOG_IN_WINS)) {
|
|
ikcp_log(kcp, IKCP_LOG_IN_WINS,
|
|
"input wins: %lu", (unsigned long)(wnd));
|
|
}
|
|
}
|
|
else {
|
|
return -3;
|
|
}
|
|
|
|
data += len;
|
|
size -= len;
|
|
}
|
|
|
|
if (flag != 0) {
|
|
ikcp_parse_fastack(kcp, maxack, latest_ts);
|
|
}
|
|
|
|
if (_itimediff(kcp->snd_una, prev_una) > 0) {
|
|
if (kcp->cwnd < kcp->rmt_wnd) {
|
|
IUINT32 mss = kcp->mss;
|
|
if (kcp->cwnd < kcp->ssthresh) {
|
|
kcp->cwnd++;
|
|
kcp->incr += mss;
|
|
} else {
|
|
if (kcp->incr < mss) kcp->incr = mss;
|
|
kcp->incr += (mss * mss) / kcp->incr + (mss / 16);
|
|
if ((kcp->cwnd + 1) * mss <= kcp->incr) {
|
|
#if 1
|
|
kcp->cwnd = (kcp->incr + mss - 1) / ((mss > 0)? mss : 1);
|
|
#else
|
|
kcp->cwnd++;
|
|
#endif
|
|
}
|
|
}
|
|
if (kcp->cwnd > kcp->rmt_wnd) {
|
|
kcp->cwnd = kcp->rmt_wnd;
|
|
kcp->incr = kcp->rmt_wnd * mss;
|
|
}
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
//---------------------------------------------------------------------
|
|
// ikcp_encode_seg
|
|
//---------------------------------------------------------------------
|
|
static char *ikcp_encode_seg(char *ptr, const IKCPSEG *seg)
|
|
{
|
|
ptr = ikcp_encode32u(ptr, seg->conv);
|
|
ptr = ikcp_encode8u(ptr, (IUINT8)seg->cmd);
|
|
ptr = ikcp_encode8u(ptr, (IUINT8)seg->frg);
|
|
ptr = ikcp_encode16u(ptr, (IUINT16)seg->wnd);
|
|
ptr = ikcp_encode32u(ptr, seg->ts);
|
|
ptr = ikcp_encode32u(ptr, seg->sn);
|
|
ptr = ikcp_encode32u(ptr, seg->una);
|
|
ptr = ikcp_encode32u(ptr, seg->len);
|
|
return ptr;
|
|
}
|
|
|
|
static int ikcp_wnd_unused(const ikcpcb *kcp)
|
|
{
|
|
if (kcp->nrcv_que < kcp->rcv_wnd) {
|
|
return kcp->rcv_wnd - kcp->nrcv_que;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
//---------------------------------------------------------------------
|
|
// ikcp_flush
|
|
//---------------------------------------------------------------------
|
|
void ikcp_flush(ikcpcb *kcp)
|
|
{
|
|
IUINT32 current = kcp->current;
|
|
char *buffer = kcp->buffer;
|
|
char *ptr = buffer;
|
|
int count, size, i;
|
|
IUINT32 resent, cwnd;
|
|
IUINT32 rtomin;
|
|
struct IQUEUEHEAD *p;
|
|
int change = 0;
|
|
int lost = 0;
|
|
IKCPSEG seg;
|
|
|
|
// 'ikcp_update' haven't been called.
|
|
if (kcp->updated == 0) return;
|
|
|
|
seg.conv = kcp->conv;
|
|
seg.cmd = IKCP_CMD_ACK;
|
|
seg.frg = 0;
|
|
seg.wnd = ikcp_wnd_unused(kcp);
|
|
seg.una = kcp->rcv_nxt;
|
|
seg.len = 0;
|
|
seg.sn = 0;
|
|
seg.ts = 0;
|
|
|
|
// flush acknowledges
|
|
count = kcp->ackcount;
|
|
for (i = 0; i < count; i++) {
|
|
size = (int)(ptr - buffer);
|
|
if (size + (int)IKCP_OVERHEAD > (int)kcp->mtu) {
|
|
ikcp_output(kcp, buffer, size);
|
|
ptr = buffer;
|
|
}
|
|
ikcp_ack_get(kcp, i, &seg.sn, &seg.ts);
|
|
ptr = ikcp_encode_seg(ptr, &seg);
|
|
}
|
|
|
|
kcp->ackcount = 0;
|
|
|
|
// probe window size (if remote window size equals zero)
|
|
if (kcp->rmt_wnd == 0) {
|
|
if (kcp->probe_wait == 0) {
|
|
kcp->probe_wait = IKCP_PROBE_INIT;
|
|
kcp->ts_probe = kcp->current + kcp->probe_wait;
|
|
}
|
|
else {
|
|
if (_itimediff(kcp->current, kcp->ts_probe) >= 0) {
|
|
if (kcp->probe_wait < IKCP_PROBE_INIT)
|
|
kcp->probe_wait = IKCP_PROBE_INIT;
|
|
kcp->probe_wait += kcp->probe_wait / 2;
|
|
if (kcp->probe_wait > IKCP_PROBE_LIMIT)
|
|
kcp->probe_wait = IKCP_PROBE_LIMIT;
|
|
kcp->ts_probe = kcp->current + kcp->probe_wait;
|
|
kcp->probe |= IKCP_ASK_SEND;
|
|
}
|
|
}
|
|
} else {
|
|
kcp->ts_probe = 0;
|
|
kcp->probe_wait = 0;
|
|
}
|
|
|
|
// flush window probing commands
|
|
if (kcp->probe & IKCP_ASK_SEND) {
|
|
seg.cmd = IKCP_CMD_WASK;
|
|
size = (int)(ptr - buffer);
|
|
if (size + (int)IKCP_OVERHEAD > (int)kcp->mtu) {
|
|
ikcp_output(kcp, buffer, size);
|
|
ptr = buffer;
|
|
}
|
|
ptr = ikcp_encode_seg(ptr, &seg);
|
|
}
|
|
|
|
// flush window probing commands
|
|
if (kcp->probe & IKCP_ASK_TELL) {
|
|
seg.cmd = IKCP_CMD_WINS;
|
|
size = (int)(ptr - buffer);
|
|
if (size + (int)IKCP_OVERHEAD > (int)kcp->mtu) {
|
|
ikcp_output(kcp, buffer, size);
|
|
ptr = buffer;
|
|
}
|
|
ptr = ikcp_encode_seg(ptr, &seg);
|
|
}
|
|
|
|
kcp->probe = 0;
|
|
|
|
// calculate window size
|
|
cwnd = _imin_(kcp->snd_wnd, kcp->rmt_wnd);
|
|
if (kcp->nocwnd == 0) cwnd = _imin_(kcp->cwnd, cwnd);
|
|
|
|
// move data from snd_queue to snd_buf
|
|
while (_itimediff(kcp->snd_nxt, kcp->snd_una + cwnd) < 0) {
|
|
IKCPSEG *newseg;
|
|
if (iqueue_is_empty(&kcp->snd_queue)) break;
|
|
|
|
newseg = iqueue_entry(kcp->snd_queue.next, IKCPSEG, node);
|
|
|
|
iqueue_del(&newseg->node);
|
|
iqueue_add_tail(&newseg->node, &kcp->snd_buf);
|
|
kcp->nsnd_que--;
|
|
kcp->nsnd_buf++;
|
|
|
|
newseg->conv = kcp->conv;
|
|
newseg->cmd = IKCP_CMD_PUSH;
|
|
newseg->wnd = seg.wnd;
|
|
newseg->ts = current;
|
|
newseg->sn = kcp->snd_nxt++;
|
|
newseg->una = kcp->rcv_nxt;
|
|
newseg->resendts = current;
|
|
newseg->rto = kcp->rx_rto;
|
|
newseg->fastack = 0;
|
|
newseg->xmit = 0;
|
|
}
|
|
|
|
// calculate resent
|
|
resent = (kcp->fastresend > 0)? (IUINT32)kcp->fastresend : 0xffffffff;
|
|
rtomin = (kcp->nodelay == 0)? (kcp->rx_rto >> 3) : 0;
|
|
|
|
// flush data segments
|
|
for (p = kcp->snd_buf.next; p != &kcp->snd_buf; p = p->next) {
|
|
IKCPSEG *segment = iqueue_entry(p, IKCPSEG, node);
|
|
int needsend = 0;
|
|
if (segment->xmit == 0) {
|
|
needsend = 1;
|
|
segment->xmit++;
|
|
segment->rto = kcp->rx_rto;
|
|
segment->resendts = current + segment->rto + rtomin;
|
|
}
|
|
else if (_itimediff(current, segment->resendts) >= 0) {
|
|
needsend = 1;
|
|
segment->xmit++;
|
|
kcp->xmit++;
|
|
if (kcp->nodelay == 0) {
|
|
segment->rto += _imax_(segment->rto, (IUINT32)kcp->rx_rto);
|
|
} else {
|
|
IINT32 step = (kcp->nodelay < 2)?
|
|
((IINT32)(segment->rto)) : kcp->rx_rto;
|
|
segment->rto += step / 2;
|
|
}
|
|
segment->resendts = current + segment->rto;
|
|
lost = 1;
|
|
}
|
|
else if (segment->fastack >= resent) {
|
|
if ((int)segment->xmit <= kcp->fastlimit ||
|
|
kcp->fastlimit <= 0) {
|
|
needsend = 1;
|
|
segment->xmit++;
|
|
segment->fastack = 0;
|
|
segment->resendts = current + segment->rto;
|
|
change++;
|
|
}
|
|
}
|
|
|
|
if (needsend) {
|
|
int need;
|
|
segment->ts = current;
|
|
segment->wnd = seg.wnd;
|
|
segment->una = kcp->rcv_nxt;
|
|
|
|
size = (int)(ptr - buffer);
|
|
need = IKCP_OVERHEAD + segment->len;
|
|
|
|
if (size + need > (int)kcp->mtu) {
|
|
ikcp_output(kcp, buffer, size);
|
|
ptr = buffer;
|
|
}
|
|
|
|
ptr = ikcp_encode_seg(ptr, segment);
|
|
|
|
if (segment->len > 0) {
|
|
memcpy(ptr, segment->data, segment->len);
|
|
ptr += segment->len;
|
|
}
|
|
|
|
if (segment->xmit >= kcp->dead_link) {
|
|
kcp->state = (IUINT32)-1;
|
|
}
|
|
}
|
|
}
|
|
|
|
// flash remain segments
|
|
size = (int)(ptr - buffer);
|
|
if (size > 0) {
|
|
ikcp_output(kcp, buffer, size);
|
|
}
|
|
|
|
// update ssthresh
|
|
if (change) {
|
|
IUINT32 inflight = kcp->snd_nxt - kcp->snd_una;
|
|
kcp->ssthresh = inflight / 2;
|
|
if (kcp->ssthresh < IKCP_THRESH_MIN)
|
|
kcp->ssthresh = IKCP_THRESH_MIN;
|
|
kcp->cwnd = kcp->ssthresh + resent;
|
|
kcp->incr = kcp->cwnd * kcp->mss;
|
|
}
|
|
|
|
if (lost) {
|
|
kcp->ssthresh = cwnd / 2;
|
|
if (kcp->ssthresh < IKCP_THRESH_MIN)
|
|
kcp->ssthresh = IKCP_THRESH_MIN;
|
|
kcp->cwnd = 1;
|
|
kcp->incr = kcp->mss;
|
|
}
|
|
|
|
if (kcp->cwnd < 1) {
|
|
kcp->cwnd = 1;
|
|
kcp->incr = kcp->mss;
|
|
}
|
|
}
|
|
|
|
|
|
//---------------------------------------------------------------------
|
|
// update state (call it repeatedly, every 10ms-100ms), or you can ask
|
|
// ikcp_check when to call it again (without ikcp_input/_send calling).
|
|
// 'current' - current timestamp in millisec.
|
|
//---------------------------------------------------------------------
|
|
void ikcp_update(ikcpcb *kcp, IUINT32 current)
|
|
{
|
|
IINT32 slap;
|
|
|
|
kcp->current = current;
|
|
|
|
if (kcp->updated == 0) {
|
|
kcp->updated = 1;
|
|
kcp->ts_flush = kcp->current;
|
|
}
|
|
|
|
slap = _itimediff(kcp->current, kcp->ts_flush);
|
|
|
|
if (slap >= 10000 || slap < -10000) {
|
|
kcp->ts_flush = kcp->current;
|
|
slap = 0;
|
|
}
|
|
|
|
if (slap >= 0) {
|
|
kcp->ts_flush += kcp->interval;
|
|
if (_itimediff(kcp->current, kcp->ts_flush) >= 0) {
|
|
kcp->ts_flush = kcp->current + kcp->interval;
|
|
}
|
|
ikcp_flush(kcp);
|
|
}
|
|
}
|
|
|
|
|
|
//---------------------------------------------------------------------
|
|
// Determine when should you invoke ikcp_update:
|
|
// returns when you should invoke ikcp_update in millisec, if there
|
|
// is no ikcp_input/_send calling. you can call ikcp_update in that
|
|
// time, instead of call update repeatly.
|
|
// Important to reduce unnacessary ikcp_update invoking. use it to
|
|
// schedule ikcp_update (eg. implementing an epoll-like mechanism,
|
|
// or optimize ikcp_update when handling massive kcp connections)
|
|
//---------------------------------------------------------------------
|
|
IUINT32 ikcp_check(const ikcpcb *kcp, IUINT32 current)
|
|
{
|
|
IUINT32 ts_flush = kcp->ts_flush;
|
|
IINT32 tm_flush = 0x7fffffff;
|
|
IINT32 tm_packet = 0x7fffffff;
|
|
IUINT32 minimal = 0;
|
|
struct IQUEUEHEAD *p;
|
|
|
|
if (kcp->updated == 0) {
|
|
return current;
|
|
}
|
|
|
|
if (_itimediff(current, ts_flush) >= 10000 ||
|
|
_itimediff(current, ts_flush) < -10000) {
|
|
ts_flush = current;
|
|
}
|
|
|
|
if (_itimediff(current, ts_flush) >= 0) {
|
|
return current;
|
|
}
|
|
|
|
tm_flush = _itimediff(ts_flush, current);
|
|
|
|
for (p = kcp->snd_buf.next; p != &kcp->snd_buf; p = p->next) {
|
|
const IKCPSEG *seg = iqueue_entry(p, const IKCPSEG, node);
|
|
IINT32 diff = _itimediff(seg->resendts, current);
|
|
if (diff <= 0) {
|
|
return current;
|
|
}
|
|
if (diff < tm_packet) tm_packet = diff;
|
|
}
|
|
|
|
minimal = (IUINT32)(tm_packet < tm_flush ? tm_packet : tm_flush);
|
|
if (minimal >= kcp->interval) minimal = kcp->interval;
|
|
|
|
return current + minimal;
|
|
}
|
|
|
|
|
|
|
|
int ikcp_setmtu(ikcpcb *kcp, int mtu)
|
|
{
|
|
char *buffer;
|
|
if (mtu < 50 || mtu < (int)IKCP_OVERHEAD)
|
|
return -1;
|
|
buffer = (char*)ikcp_malloc((mtu + IKCP_OVERHEAD) * 3);
|
|
if (buffer == NULL)
|
|
return -2;
|
|
kcp->mtu = mtu;
|
|
kcp->mss = kcp->mtu - IKCP_OVERHEAD;
|
|
ikcp_free(kcp->buffer);
|
|
kcp->buffer = buffer;
|
|
return 0;
|
|
}
|
|
|
|
int ikcp_interval(ikcpcb *kcp, int interval)
|
|
{
|
|
if (interval > 5000) interval = 5000;
|
|
else if (interval < 10) interval = 10;
|
|
kcp->interval = interval;
|
|
return 0;
|
|
}
|
|
|
|
int ikcp_nodelay(ikcpcb *kcp, int nodelay, int interval, int resend, int nc)
|
|
{
|
|
if (nodelay >= 0) {
|
|
kcp->nodelay = nodelay;
|
|
if (nodelay) {
|
|
kcp->rx_minrto = IKCP_RTO_NDL;
|
|
}
|
|
else {
|
|
kcp->rx_minrto = IKCP_RTO_MIN;
|
|
}
|
|
}
|
|
if (interval >= 0) {
|
|
if (interval > 5000) interval = 5000;
|
|
else if (interval < 10) interval = 10;
|
|
kcp->interval = interval;
|
|
}
|
|
if (resend >= 0) {
|
|
kcp->fastresend = resend;
|
|
}
|
|
if (nc >= 0) {
|
|
kcp->nocwnd = nc;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
int ikcp_wndsize(ikcpcb *kcp, int sndwnd, int rcvwnd)
|
|
{
|
|
if (kcp) {
|
|
if (sndwnd > 0) {
|
|
kcp->snd_wnd = sndwnd;
|
|
}
|
|
if (rcvwnd > 0) { // must >= max fragment size
|
|
kcp->rcv_wnd = _imax_(rcvwnd, IKCP_WND_RCV);
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int ikcp_waitsnd(const ikcpcb *kcp)
|
|
{
|
|
return kcp->nsnd_buf + kcp->nsnd_que;
|
|
}
|
|
|
|
|
|
// read conv
|
|
IUINT32 ikcp_getconv(const void *ptr)
|
|
{
|
|
IUINT32 conv;
|
|
ikcp_decode32u((const char*)ptr, &conv);
|
|
return conv;
|
|
}
|
|
|
|
|