基于asio的C++17网络库knet设计源码

//===================================================================== // // KCP - A Better ARQ Protocol Implementation // skywind3000 (at) gmail.com, 2010-2011 // // Features: // + Average RTT reduce 30% - 40% vs traditional ARQ like tcp. // + Maximum RTT reduce three times vs tcp. // + Lightweight, distributed as a single source file. // //===================================================================== #include "ikcp.h" #include <stddef.h> #include <stdlib.h> #include <string.h> #include <stdarg.h> #include <stdio.h> //--------------------------------------------------------------------- // encode / decode //--------------------------------------------------------------------- /* encode 8 bits unsigned int */ static inline char *ikcp_encode8u(char *p, unsigned char c) { *(unsigned char*)p++ = c; return p; } /* decode 8 bits unsigned int */ static inline const char *ikcp_decode8u(const char *p, unsigned char *c) { *c = *(unsigned char*)p++; return p; } /* encode 16 bits unsigned int (lsb) */ static inline char *ikcp_encode16u(char *p, unsigned short w) { #if IWORDS_BIG_ENDIAN || IWORDS_MUST_ALIGN *(unsigned char*)(p + 0) = (w & 255); *(unsigned char*)(p + 1) = (w >> 8); #else *(unsigned short*)(p) = w; #endif p += 2; return p; } /* decode 16 bits unsigned int (lsb) */ static inline const char *ikcp_decode16u(const char *p, unsigned short *w) { #if IWORDS_BIG_ENDIAN || IWORDS_MUST_ALIGN *w = *(const unsigned char*)(p + 1); *w = *(const unsigned char*)(p + 0) + (*w << 8); #else *w = *(const unsigned short*)p; #endif p += 2; return p; } /* encode 32 bits unsigned int (lsb) */ static inline char *ikcp_encode32u(char *p, IUINT32 l) { #if IWORDS_BIG_ENDIAN || IWORDS_MUST_ALIGN *(unsigned char*)(p + 0) = (unsigned char)((l >> 0) & 0xff); *(unsigned char*)(p + 1) = (unsigned char)((l >> 8) & 0xff); *(unsigned char*)(p + 2) = (unsigned char)((l >> 16) & 0xff); *(unsigned char*)(p + 3) = (unsigned char)((l >> 24) & 0xff); #else *(IUINT32*)p = l; #endif p += 4; return p; } /* decode 32 bits unsigned int (lsb) */ static inline const char *ikcp_decode32u(const char *p, IUINT32 *l) { #if IWORDS_BIG_ENDIAN || IWORDS_MUST_ALIGN *l = *(const unsigned char*)(p + 3); *l = *(const unsigned char*)(p + 2) + (*l << 8); *l = *(const unsigned char*)(p + 1) + (*l << 8); *l = *(const unsigned char*)(p + 0) + (*l << 8); #else *l = *(const IUINT32*)p; #endif p += 4; return p; } static inline IUINT32 _imin_(IUINT32 a, IUINT32 b) { return a <= b ? a : b; } static inline IUINT32 _imax_(IUINT32 a, IUINT32 b) { return a >= b ? a : b; } static inline IUINT32 _ibound_(IUINT32 lower, IUINT32 middle, IUINT32 upper) { return _imin_(_imax_(lower, middle), upper); } static inline long _itimediff(IUINT32 later, IUINT32 earlier) { return ((IINT32)(later - earlier)); } //--------------------------------------------------------------------- // manage segment //--------------------------------------------------------------------- typedef struct IKCPSEG IKCPSEG; static void* (*ikcp_malloc_hook)(size_t) = NULL; static void (*ikcp_free_hook)(void *) = NULL; // internal malloc static void* ikcp_malloc(size_t size) { if (ikcp_malloc_hook) return ikcp_malloc_hook(size); return malloc(size); } // internal free static void ikcp_free(void *ptr) { if (ikcp_free_hook) { ikcp_free_hook(ptr); } else { free(ptr); } } // redefine allocator void ikcp_allocator(void* (*new_malloc)(size_t), void (*new_free)(void*)) { ikcp_malloc_hook = new_malloc; ikcp_free_hook = new_free; } // allocate a new kcp segment static IKCPSEG* ikcp_segment_new(ikcpcb *kcp, int size) { return (IKCPSEG*)ikcp_malloc(sizeof(IKCPSEG) + size); } // delete a segment static void ikcp_segment_delete(ikcpcb *kcp, IKCPSEG *seg) { ikcp_free(seg); } // write log void ikcp_log(ikcpcb *kcp, int mask, const char *fmt, ...) { char buffer[1024]; va_list argptr; if ((mask & kcp->logmask) == 0 || kcp->writelog == 0) return; va_start(argptr, fmt); vsprintf(buffer, fmt, argptr); va_end(argptr); kcp->writelog(buffer, kcp, kcp->user); } // check log mask static int ikcp_canlog(const ikcpcb *kcp, int mask) { if ((mask & kcp->logmask) == 0 || kcp->writelog == NULL) return 0; return 1; } // output segment static int ikcp_output(ikcpcb *kcp, const void *data, int size) { assert(kcp); assert(kcp->output); if (ikcp_canlog(kcp, IKCP_LOG_OUTPUT)) { ikcp_log(kcp, IKCP_LOG_OUTPUT, "[RO] %ld bytes", (long)size); } if (size == 0) return 0; return kcp->output((const char*)data, size, kcp, kcp->user); } // output queue void ikcp_qprint(const char *name, const struct IQUEUEHEAD *head) { #if 0 const struct IQUEUEHEAD *p; printf("<%s>: [", name); for (p = head->next; p != head; p = p->next) { const IKCPSEG *seg = iqueue_entry(p, const IKCPSEG, node); printf("(%lu %d)", (unsigned long)seg->sn, (int)(seg->ts % 10000)); if (p->next != head) printf(","); } printf("]\n"); #endif } //--------------------------------------------------------------------- // create a new kcpcb //--------------------------------------------------------------------- ikcpcb* ikcp_create(IUINT32 conv, void *user) { ikcpcb *kcp = (ikcpcb*)ikcp_malloc(sizeof(struct IKCPCB)); if (kcp == NULL) return NULL; kcp->conv = conv; kcp->user = user; kcp->snd_una = 0; kcp->snd_nxt = 0; kcp->rcv_nxt = 0; kcp->ts_recent = 0; kcp->ts_lastack = 0; kcp->ts_probe = 0; kcp->probe_wait = 0; kcp->snd_wnd = IKCP_WND_SND; kcp->rcv_wnd = IKCP_WND_RCV; kcp->rmt_wnd = IKCP_WND_RCV; kcp->cwnd = 0; kcp->incr = 0; kcp->probe = 0; kcp->mtu = IKCP_MTU_DEF; kcp->mss = kcp->mtu - IKCP_OVERHEAD; kcp->stream = 0; kcp->buffer = (char*)ikcp_malloc((kcp->mtu + IKCP_OVERHEAD) * 3); if (kcp->buffer == NULL) { ikcp_free(kcp); return NULL; } iqueue_init(&kcp->snd_queue); iqueue_init(&kcp->rcv_queue); iqueue_init(&kcp->snd_buf); iqueue_init(&kcp->rcv_buf); kcp->nrcv_buf = 0; kcp->nsnd_buf = 0; kcp->nrcv_que = 0; kcp->nsnd_que = 0; kcp->state = 0; kcp->acklist = NULL; kcp->ackblock = 0; kcp->ackcount = 0; kcp->rx_srtt = 0; kcp->rx_rttval = 0; kcp->rx_rto = IKCP_RTO_DEF; kcp->rx_minrto = IKCP_RTO_MIN; kcp->current = 0; kcp->interval = IKCP_INTERVAL; kcp->ts_flush = IKCP_INTERVAL; kcp->nodelay = 0; kcp->updated = 0; kcp->logmask = 0; kcp->ssthresh = IKCP_THRESH_INIT; kcp->fastresend = 0; kcp->fastlimit = IKCP_FASTACK_LIMIT; kcp->nocwnd = 0; kcp->xmit = 0; kcp->dead_link = IKCP_DEADLINK; kcp->output = NULL; kcp->writelog = NULL; return kcp; } //--------------------------------------------------------------------- // release a new kcpcb //--------------------------------------------------------------------- void ikcp_release(ikcpcb *kcp) { assert(kcp); if (kcp) { IKCPSEG *seg; while (!iqueue_is_empty(&kcp->snd_buf)) { seg = iqueue_entry(kcp->snd_buf.next, IKCPSEG, node); iqueue_del(&seg->node); ikcp_segment_delete(kcp, seg); } while (!iqueue_is_empty(&kcp->rcv_buf)) { seg = iqueue_entry(kcp->rcv_buf.next, IKCPSEG, node); iqueue_del(&seg->node); ikcp_segment_delete(kcp, seg); } while (!iqueue_is_empty(&kcp->snd_queue)) { seg = iqueue_entry(kcp->snd_queue.next, IKCPSEG, node); iqueue_del(&seg->node); ikcp_segment_delete(kcp, seg); } while (!iqueue_is_empty(&kcp->rcv_queue)) { seg = iqueue_entry(kcp->rcv_queue.next, IKCPSEG, node); iqueue_del(&seg->node); ikcp_segment_delete(kcp, seg); } if (kcp->buffer) { ikcp_free(kcp->buffer); } if (kcp->acklist) { ikcp_free(kcp->acklist); } kcp->nrcv_buf = 0; kcp->nsnd_buf = 0; kcp->nrcv_que = 0; kcp->nsnd_que = 0; kcp->ackcount = 0; kcp->buffer = NULL; k