mirror of
https://github.com/yarrick/iodine.git
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Created sliding window buffer implementation and handling code
This commit is contained in:
frekky
parent
709afb8569
commit
92f3963790
@ -1,4 +1,4 @@
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COMMONOBJS = tun.o dns.o read.o encoding.o login.o base32.o base64.o base64u.o base128.o md5.o common.o
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COMMONOBJS = tun.o dns.o read.o encoding.o login.o base32.o base64.o base64u.o base128.o md5.o window.o common.o
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CLIENTOBJS = iodine.o client.o util.o
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CLIENT = ../bin/iodine
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SERVEROBJS = iodined.o user.o fw_query.o
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292
src/window.c
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292
src/window.c
Normal file
@ -0,0 +1,292 @@
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/*
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* Copyright (c) 2015 Frekk van Blagh
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <unistd.h>
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#include <stdint.h>
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#include <time.h>
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#include <stdio.h>
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#include <err.h>
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#include <string.h>
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#include <stdlib.h>
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#include "common.h"
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#include "window.h"
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struct frag_buffer *
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window_buffer_init(size_t length, unsigned windowsize, unsigned fragsize, int dir)
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{
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struct frag_buffer *buf;
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buf = calloc(sizeof(struct frag_buffer), 1);
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if (!buf) {
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errx(1, "Failed to allocate window buffer memory!");
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}
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if (dir != WINDOW_RECVING && dir != WINDOW_SENDING) {
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errx(1, "Invalid window direction!");
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}
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if (fragsize > MAX_FRAGSIZE) {
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errx(fragsize, "Fragsize too large! Please recompile with larger MAX_FRAGSIZE!");
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}
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buf->frags = calloc(length, sizeof(fragment));
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if (!buf->frags) {
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errx(1, "Failed to allocate fragment buffer!");
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}
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buf->length = length;
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buf->windowsize = windowsize;
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buf->maxfraglen = fragsize;
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buf->window_end = AFTER(buf, windowsize);
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buf->direction = dir;
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return buf;
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}
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void
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window_buffer_destroy(struct frag_buffer *w)
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{
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free(w->frags);
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free(w);
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}
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/* Returns number of available fragment slots (NOT BYTES) */
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size_t
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window_buffer_available(struct frag_buffer *w)
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{
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return w->length - w->numitems;
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}
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/* Places a fragment in the window after the last one */
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int
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window_append_fragment(struct frag_buffer *w, fragment *src)
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{
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if (window_buffer_available(w) < 1) return 0;
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memcpy(&w->frags[w->last_write], src, sizeof(fragment));
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w->last_write = WRAP(w->last_write + 1);
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w->numitems ++;
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return 1;
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}
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/* Handles fragment received from the sending side (RECV) */
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int
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window_process_incoming_fragment(struct frag_buffer *w, fragment *f)
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{
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/* Check if packet is in window */
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unsigned startid, endid;
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fragment *fd;
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startid = w->start_seq_id;
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endid = (w->start_seq_id + w->windowsize) % MAX_SEQ_ID;
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if (!INWINDOW_SEQ(startid, endid, f->seqID)) {
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warnx("Dropping frag with seqID %u: not in window (%u-%u)\n", f->seqID, startid, endid);
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return 0;
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}
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/* Place fragment into correct location in buffer */
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size_t dest = WRAP(w->window_start + SEQ_OFFSET(startid, f->seqID));
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// warnx(" Putting frag seq %u into frags[%lu + %u = %lu]", f->seqID, w->window_start, SEQ_OFFSET(startid, f->seqID), dest);
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/* Check if fragment already received */
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fd = &w->frags[dest];
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if (fd->len != 0) {
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warnx("Received duplicate frag, dropping. (prev %u/new %u)", fd->seqID, f->seqID);
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return 0;
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}
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memcpy(&fd, f, sizeof(fragment));
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fd->retries = 0;
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fd->ack_other = -1;
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fd->acks = 0;
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w->numitems ++;
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return 1;
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}
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/* Reassembles first complete sequence of fragments into data. (RECV)
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* Returns length of data reassembled, or 0 if no data reassembled */
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size_t
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window_reassemble_data(struct frag_buffer *w, uint8_t *data, unsigned maxlen, int *compression)
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{
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size_t woffs, fraglen, datalen = 0;
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uint8_t *dest; //, *fdata_start;
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dest = data;
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if (w->frags[w->chunk_start].start == 0) {
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// warnx("chunk_start pointing to non-start fragment (%u)!", w->frags[w->chunk_start].seqID);
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return 0;
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}
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*compression = 1;
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fragment *f;
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size_t i, curseq;
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curseq = w->frags[w->chunk_start].seqID;
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for (i = 0; i < w->numitems; ++i) {
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woffs = WRAP(w->chunk_start + i);
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f = &w->frags[woffs];
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fraglen = f->len;
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if (fraglen == 0 || !f->data || f->seqID != curseq) {
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// warnx("data missing! Not reassembling!");
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return 0;
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}
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// warnx(" Fragment seq %u, data length %u, data offset %lu, total len %u, maxlen %u",
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// f->seqID, fraglen, dest - data, datalen, maxlen);
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memcpy(dest, f->data, MIN(fraglen, maxlen));
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dest += fraglen;
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datalen += fraglen;
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*compression &= f->compressed & 1;
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if (f->compressed != *compression) {
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warnx("Inconsistent compression flags in chunk. Not reassembling!");
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return 0;
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}
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if (fraglen > maxlen) {
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warnx("Data buffer too small! Reassembled %lu bytes.", datalen);
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return 0;
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}
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if (f->end == 1) {
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// warnx("Found end of chunk! (seqID %u, chunk len %u, datalen %u)", f->seqID, i, datalen);
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break;
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}
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/* Move window along to avoid weird issues */
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if (INWINDOW_INDEX(w, woffs)) {
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window_tick(w);
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}
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/* Clear fragment */
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memset(f, 0, sizeof(fragment));
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maxlen -= fraglen;
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curseq = (curseq + 1) % MAX_SEQ_ID;
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}
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w->chunk_start = WRAP(woffs + 1);
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w->numitems -= i + 1;
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return datalen;
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}
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/* Returns next fragment to be sent or NULL if nothing (SEND)
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* This also handles packet resends, timeouts etc. */
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fragment *
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window_get_next_sending_fragment(struct frag_buffer *w, int other_ack)
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{
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fragment *f;
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if (other_ack >= MAX_SEQ_ID || other_ack < 0)
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other_ack = -1;
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for (size_t i = 0; i < w->windowsize; i++) {
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f = &w->frags[WRAP(w->window_start + i)];
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if (f->acks >= 1) continue;
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if (f->retries >= 1 && difftime(f->lastsent, time(NULL)) > ACK_TIMEOUT) {
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/* Fragment sent before, not ACK'd */
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warnx("Sending fragment %u again, %u retries so far, %u resent overall\n", f->seqID, f->retries, w->resends);
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w->resends ++;
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goto found;
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} else if (f->retries == 0 && f->len > 0) {
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/* Fragment not sent */
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goto found;
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}
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}
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// warnx("Not sending any fragments (last frag checked: retries %u, seqid %u, len %lu)",
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// f->retries, f->seqID, f->len);
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// TODO: statistics for packet loss/not sending etc
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return NULL;
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found:
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/* store other ACK into fragment so ACK is resent if fragment times out */
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if (f->ack_other == -1)
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f->ack_other = other_ack;
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f->is_nack &= 1;
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f->start &= 1;
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f->end &= 1;
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f->retries++;
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time(&f->lastsent);
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return f;
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}
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/* Gets the seqid of next fragment to be ACK'd (RECV) */
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int
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window_get_next_ack(struct frag_buffer *w)
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{
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fragment *f;
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for (size_t i = 0; i < w->windowsize; i++) {
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f = &w->frags[WRAP(w->window_start + i)];
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if (f->len > 0 && f->acks <= 0) {
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f->acks = 1;
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return f->seqID;
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}
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}
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return -1;
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}
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/* Sets the fragment with seqid to be ACK'd (SEND) */
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void
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window_ack(struct frag_buffer *w, int seqid)
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{
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fragment *f;
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if (seqid < 0 || seqid > MAX_SEQ_ID) return;
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for (size_t i = 0; i < w->windowsize; i++) {
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f = &w->frags[AFTER(w, i)];
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if (f->seqID == seqid) {
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if (f->acks > 0) warnx("Duplicate ack for seqId %u", seqid);
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f->acks ++;
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// warnx(" ack frag seq %u, ACKs %u, len %lu, s %u e %u", f->seqID, f->ack, f->len, f->start, f->end);
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}
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}
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}
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/* Function to be called after all other processing has been done
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* when anything happens (moves window etc) (SEND/RECV) */
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void
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window_tick(struct frag_buffer *w)
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{
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for (size_t i = 0; i < w->windowsize; i++) {
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if (w->frags[w->window_start].acks >= 1) {
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// warnx("moving window forwards 1; start = %lu-%lu, end = %lu-%lu, len = %lu",
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// w->window_start, AFTER(w, 1), w->window_end, AFTER(w, w->windowsize + 1), w->length);
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if (w->direction == WINDOW_SENDING) {
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w->numitems --; /* Clear old fragments */
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memset(&w->frags[w->window_start], 0, sizeof(fragment));
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}
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w->window_start = AFTER(w, 1);
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w->start_seq_id = (w->start_seq_id + 1) % MAX_SEQ_ID;
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w->window_end = AFTER(w, w->windowsize);
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} else break;
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}
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}
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/* Splits data into fragments and adds to the end of the window buffer for sending
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* All fragment meta-data is created here (SEND) */
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int
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window_add_outgoing_data(struct frag_buffer *w, uint8_t *data, size_t len, int compressed)
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{
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// Split data into thingies of <= fragsize
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size_t n = ((len - 1) / w->maxfraglen) + 1;
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if (!data || n == 0 || len == 0 || n > window_buffer_available(w)) {
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warnx("Failed to append fragment (buffer too small!)");
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return -1;
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}
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compressed &= 1;
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size_t offset = 0;
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static fragment f;
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// warnx("add data len %lu, %lu frags, max fragsize %u", len, n, w->maxfraglen);
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for (size_t i = 0; i < n; i++) {
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memset(&f, 0, sizeof(f));
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f.len = MIN(len - offset, w->maxfraglen);
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memcpy(f.data, data + offset, f.len);
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f.seqID = w->cur_seq_id;
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f.start = (i == 0) ? 1 : 0;
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f.end = (i == n - 1) ? 1 : 0;
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f.compressed = compressed;
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f.ack_other = -1;
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window_append_fragment(w, &f);
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w->cur_seq_id = (w->cur_seq_id + 1) % MAX_SEQ_ID;
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// warnx(" a = %u, b = %u, a %% b = %u", (len - offset), (w->maxfraglen + 1), (len - offset) % (w->maxfraglen + 1));
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// warnx(" fragment len %lu, seqID %u, s %u, end %u, dOffs %lu", f.len, f.seqID, f.start, f.end, offset);
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offset += f.len;
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}
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return n;
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}
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108
src/window.h
Normal file
108
src/window.h
Normal file
@ -0,0 +1,108 @@
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/*
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* Copyright (c) 2015 Frekk van Blagh
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
|
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
|
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
|
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
|
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
|
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
|
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#ifndef __WINDOW_H__
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#define __WINDOW_H__
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#define MAX_SEQ_ID 256
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#define MAX_FRAGSIZE 2048
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#define ACK_TIMEOUT 5
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#define WINDOW_SENDING 1
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#define WINDOW_RECVING 0
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typedef struct fragment {
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size_t len; /* Length of fragment data */
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unsigned seqID; /* fragment sequence ID */
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int ack_other; /* other way ACK seqID (>=0) or unset (<0) */
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int is_nack; /* 1 if other way ACK is a NACK */
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int compressed; /* compression flag */
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uint8_t start; /* start of chunk flag */
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uint8_t end; /* end of chunk flag */
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uint8_t data[MAX_FRAGSIZE]; /* fragment data */
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unsigned retries; /* number of times fragment has been sent */
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time_t lastsent; /* timestamp of most recent send attempt TODO: millisecond precision*/
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int acks; /* number of times packet has been ack'd (should be <= 1) */
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} fragment;
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struct frag_buffer {
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fragment *frags; /* pointer to array of data fragments */
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unsigned windowsize; /* Max number of packets in flight */
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unsigned maxfraglen; /* Max fragment size */
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size_t length; /* Length of buffer */
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size_t numitems; /* number of non-empty fragments stored in buffer */
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size_t window_start; /* Start of window */
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size_t window_end; /* End of window (index) */
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// size_t last_sent; /* Last fragment sent (index) */
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size_t last_write; /* Last fragment read/written */
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size_t chunk_start; /* Start of current chunk of fragments, ie where fragno = 0 */
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unsigned cur_seq_id; /* Most recent sequence ID */
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unsigned start_seq_id; /* Start of window sequence ID */
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unsigned resends; /* number of fragments resent */
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int direction; /* Sending or recving */
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};
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#define AFTER(w, o) ((w->window_start + o) % w->length)
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// Distance (going forwards) between a and b in window of length l
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#define DISTF(l, a, b) (((a > b) ? a-b : l-a+b-1) % l)
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// Distance backwards between a and b in window of length l
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#define DISTB(l, a, b) (((a < b) ? l-b+a-1 : a-b) % l)
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#define INWINDOW_INDEX(w, a) ((w->window_start < w->window_end) ? \
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(a >= w->window_start && a <= w->window_end) : \
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((a >= w->window_start && a <= w->length - 1) || \
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(a >= 0 && a <= w->window_end)))
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#define INWINDOW_SEQ(start, end, a) ((start < end) ? \
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(a >= start && a <= end) : \
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((a >= start && a <= MAX_SEQ_ID - 1) || \
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(a <= end)))
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#define SEQ_OFFSET(start, a) ((a >= start) ? a - start : MAX_SEQ_ID + start - a - 1)
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#define WRAP(x) ((x) % w->length)
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struct frag_buffer *window_buffer_init(size_t length, unsigned windowsize, unsigned fragsize, int dir);
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void window_buffer_destroy(struct frag_buffer *w);
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/* Returns number of available fragment slots (NOT BYTES) */
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size_t window_buffer_available(struct frag_buffer *w);
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/* Places a fragment in the window after the last one */
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int window_append_fragment(struct frag_buffer *w, fragment *src);
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/* Handles fragment received from the sending side (RECV) */
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int window_process_incoming_fragment(struct frag_buffer *w, fragment *f);
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/* Reassembles first complete sequence of fragments into data. (RECV)
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* Returns length of data reassembled, or 0 if no data reassembled */
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size_t window_reassemble_data(struct frag_buffer *w, uint8_t *data, unsigned maxlen, int *compression);
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/* Returns next fragment to be sent or NULL if nothing (SEND) */
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fragment *window_get_next_sending_fragment(struct frag_buffer *w, int other_ack);
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/* Gets the seqid of next fragment to be ACK'd (RECV) */
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int window_get_next_ack(struct frag_buffer *w);
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/* Sets the fragment with seqid to be ACK'd (SEND) */
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void window_ack(struct frag_buffer *w, unsigned seqid);
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/* To be called after all other processing has been done
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* when anything happens (moves window etc) (SEND/RECV) */
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void window_tick(struct frag_buffer *w);
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/* Splits data into fragments and adds to the end of the window buffer for sending
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* All fragment meta-data is created here (SEND) */
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int window_add_outgoing_data(struct frag_buffer *w, uint8_t *data, size_t len, int compressed);
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#endif /* __WINDOW_H__ */
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