--- /dev/null
+/*
+ * fec.c -- forward error correction based on Vandermonde matrices
+ * 980624
+ * (C) 1997-98 Luigi Rizzo (luigi@iet.unipi.it)
+ *
+ * Portions derived from code by Phil Karn (karn@ka9q.ampr.org),
+ * Robert Morelos-Zaragoza (robert@spectra.eng.hawaii.edu) and Hari
+ * Thirumoorthy (harit@spectra.eng.hawaii.edu), Aug 1995
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials
+ * provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+ * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
+ * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
+ * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ */
+
+/*
+ * The following parameter defines how many bits are used for
+ * field elements. The code supports any value from 2 to 16
+ * but fastest operation is achieved with 8 bit elements
+ * This is the only parameter you may want to change.
+ */
+#ifndef GF_BITS
+#define GF_BITS 8 /* code over GF(2**GF_BITS) - change to suit */
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/*
+ * compatibility stuff
+ */
+#ifdef MSDOS /* but also for others, e.g. sun... */
+#define NEED_BCOPY
+#define bcmp(a,b,n) memcmp(a,b,n)
+#endif
+
+#ifdef NEED_BCOPY
+#define bcopy(s, d, siz) memcpy((d), (s), (siz))
+#define bzero(d, siz) memset((d), '\0', (siz))
+#endif
+
+/*
+ * stuff used for testing purposes only
+ */
+
+#ifdef TEST
+#define DEB(x)
+#define DDB(x) x
+#define DEBUG 0 /* minimal debugging */
+#ifdef MSDOS
+#include <time.h>
+struct timeval {
+ unsigned long ticks;
+};
+#define gettimeofday(x, dummy) { (x)->ticks = clock() ; }
+#define DIFF_T(a,b) (1+ 1000000*(a.ticks - b.ticks) / CLOCKS_PER_SEC )
+typedef unsigned long u_long ;
+typedef unsigned short u_short ;
+#else /* typically, unix systems */
+#include <sys/time.h>
+#define DIFF_T(a,b) \
+ (1+ 1000000*(a.tv_sec - b.tv_sec) + (a.tv_usec - b.tv_usec) )
+#endif
+
+#define TICK(t) \
+ {struct timeval x ; \
+ gettimeofday(&x, NULL) ; \
+ t = x.tv_usec + 1000000* (x.tv_sec & 0xff ) ; \
+ }
+#define TOCK(t) \
+ { u_long t1 ; TICK(t1) ; \
+ if (t1 < t) t = 256000000 + t1 - t ; \
+ else t = t1 - t ; \
+ if (t == 0) t = 1 ;}
+
+u_long ticks[10]; /* vars for timekeeping */
+#else
+#define DEB(x)
+#define DDB(x)
+#define TICK(x)
+#define TOCK(x)
+#endif /* TEST */
+
+/*
+ * You should not need to change anything beyond this point.
+ * The first part of the file implements linear algebra in GF.
+ *
+ * gf is the type used to store an element of the Galois Field.
+ * Must constain at least GF_BITS bits.
+ *
+ * Note: unsigned char will work up to GF(256) but int seems to run
+ * faster on the Pentium. We use int whenever have to deal with an
+ * index, since they are generally faster.
+ */
+#if (GF_BITS < 2 && GF_BITS >16)
+#error "GF_BITS must be 2 .. 16"
+#endif
+#if (GF_BITS <= 8)
+typedef unsigned char gf;
+#else
+typedef unsigned short gf;
+#endif
+
+#define GF_SIZE ((1 << GF_BITS) - 1) /* powers of \alpha */
+
+/*
+ * Primitive polynomials - see Lin & Costello, Appendix A,
+ * and Lee & Messerschmitt, p. 453.
+ */
+static char *allPp[] = { /* GF_BITS polynomial */
+ NULL, /* 0 no code */
+ NULL, /* 1 no code */
+ "111", /* 2 1+x+x^2 */
+ "1101", /* 3 1+x+x^3 */
+ "11001", /* 4 1+x+x^4 */
+ "101001", /* 5 1+x^2+x^5 */
+ "1100001", /* 6 1+x+x^6 */
+ "10010001", /* 7 1 + x^3 + x^7 */
+ "101110001", /* 8 1+x^2+x^3+x^4+x^8 */
+ "1000100001", /* 9 1+x^4+x^9 */
+ "10010000001", /* 10 1+x^3+x^10 */
+ "101000000001", /* 11 1+x^2+x^11 */
+ "1100101000001", /* 12 1+x+x^4+x^6+x^12 */
+ "11011000000001", /* 13 1+x+x^3+x^4+x^13 */
+ "110000100010001", /* 14 1+x+x^6+x^10+x^14 */
+ "1100000000000001", /* 15 1+x+x^15 */
+ "11010000000010001" /* 16 1+x+x^3+x^12+x^16 */
+};
+
+
+/*
+ * To speed up computations, we have tables for logarithm, exponent
+ * and inverse of a number. If GF_BITS <= 8, we use a table for
+ * multiplication as well (it takes 64K, no big deal even on a PDA,
+ * especially because it can be pre-initialized an put into a ROM!),
+ * otherwhise we use a table of logarithms.
+ * In any case the macro gf_mul(x,y) takes care of multiplications.
+ */
+
+static gf gf_exp[2*GF_SIZE]; /* index->poly form conversion table */
+static int gf_log[GF_SIZE + 1]; /* Poly->index form conversion table */
+static gf inverse[GF_SIZE+1]; /* inverse of field elem. */
+ /* inv[\alpha**i]=\alpha**(GF_SIZE-i-1) */
+
+/*
+ * modnn(x) computes x % GF_SIZE, where GF_SIZE is 2**GF_BITS - 1,
+ * without a slow divide.
+ */
+static inline gf
+modnn(int x)
+{
+ while (x >= GF_SIZE) {
+ x -= GF_SIZE;
+ x = (x >> GF_BITS) + (x & GF_SIZE);
+ }
+ return x;
+}
+
+#define SWAP(a,b,t) {t tmp; tmp=a; a=b; b=tmp;}
+
+/*
+ * gf_mul(x,y) multiplies two numbers. If GF_BITS<=8, it is much
+ * faster to use a multiplication table.
+ *
+ * USE_GF_MULC, GF_MULC0(c) and GF_ADDMULC(x) can be used when multiplying
+ * many numbers by the same constant. In this case the first
+ * call sets the constant, and others perform the multiplications.
+ * A value related to the multiplication is held in a local variable
+ * declared with USE_GF_MULC . See usage in addmul1().
+ */
+#if (GF_BITS <= 8)
+static gf gf_mul_table[GF_SIZE + 1][GF_SIZE + 1];
+
+#define gf_mul(x,y) gf_mul_table[x][y]
+
+#define USE_GF_MULC register gf * __gf_mulc_
+#define GF_MULC0(c) __gf_mulc_ = gf_mul_table[c]
+#define GF_ADDMULC(dst, x) dst ^= __gf_mulc_[x]
+
+static void
+init_mul_table()
+{
+ int i, j;
+ for (i=0; i< GF_SIZE+1; i++)
+ for (j=0; j< GF_SIZE+1; j++)
+ gf_mul_table[i][j] = gf_exp[modnn(gf_log[i] + gf_log[j]) ] ;
+
+ for (j=0; j< GF_SIZE+1; j++)
+ gf_mul_table[0][j] = gf_mul_table[j][0] = 0;
+}
+#else /* GF_BITS > 8 */
+static inline gf
+gf_mul(x,y)
+{
+ if ( (x) == 0 || (y)==0 ) return 0;
+
+ return gf_exp[gf_log[x] + gf_log[y] ] ;
+}
+#define init_mul_table()
+
+#define USE_GF_MULC register gf * __gf_mulc_
+#define GF_MULC0(c) __gf_mulc_ = &gf_exp[ gf_log[c] ]
+#define GF_ADDMULC(dst, x) { if (x) dst ^= __gf_mulc_[ gf_log[x] ] ; }
+#endif
+
+/*
+ * Generate GF(2**m) from the irreducible polynomial p(X) in p[0]..p[m]
+ * Lookup tables:
+ * index->polynomial form gf_exp[] contains j= \alpha^i;
+ * polynomial form -> index form gf_log[ j = \alpha^i ] = i
+ * \alpha=x is the primitive element of GF(2^m)
+ *
+ * For efficiency, gf_exp[] has size 2*GF_SIZE, so that a simple
+ * multiplication of two numbers can be resolved without calling modnn
+ */
+
+/*
+ * i use malloc so many times, it is easier to put checks all in
+ * one place.
+ */
+static void *
+my_malloc(int sz, char *err_string)
+{
+ void *p = malloc( sz );
+ if (p == NULL) {
+ fprintf(stderr, "-- malloc failure allocating %s\n", err_string);
+ exit(1) ;
+ }
+ return p ;
+}
+
+#define NEW_GF_MATRIX(rows, cols) \
+ (gf *)my_malloc(rows * cols * sizeof(gf), " ## __LINE__ ## " )
+
+/*
+ * initialize the data structures used for computations in GF.
+ */
+static void
+generate_gf(void)
+{
+ int i;
+ gf mask;
+ char *Pp = allPp[GF_BITS] ;
+
+ mask = 1; /* x ** 0 = 1 */
+ gf_exp[GF_BITS] = 0; /* will be updated at the end of the 1st loop */
+ /*
+ * first, generate the (polynomial representation of) powers of \alpha,
+ * which are stored in gf_exp[i] = \alpha ** i .
+ * At the same time build gf_log[gf_exp[i]] = i .
+ * The first GF_BITS powers are simply bits shifted to the left.
+ */
+ for (i = 0; i < GF_BITS; i++, mask <<= 1 ) {
+ gf_exp[i] = mask;
+ gf_log[gf_exp[i]] = i;
+ /*
+ * If Pp[i] == 1 then \alpha ** i occurs in poly-repr
+ * gf_exp[GF_BITS] = \alpha ** GF_BITS
+ */
+ if ( Pp[i] == '1' )
+ gf_exp[GF_BITS] ^= mask;
+ }
+ /*
+ * now gf_exp[GF_BITS] = \alpha ** GF_BITS is complete, so can als
+ * compute its inverse.
+ */
+ gf_log[gf_exp[GF_BITS]] = GF_BITS;
+ /*
+ * Poly-repr of \alpha ** (i+1) is given by poly-repr of
+ * \alpha ** i shifted left one-bit and accounting for any
+ * \alpha ** GF_BITS term that may occur when poly-repr of
+ * \alpha ** i is shifted.
+ */
+ mask = 1 << (GF_BITS - 1 ) ;
+ for (i = GF_BITS + 1; i < GF_SIZE; i++) {
+ if (gf_exp[i - 1] >= mask)
+ gf_exp[i] = gf_exp[GF_BITS] ^ ((gf_exp[i - 1] ^ mask) << 1);
+ else
+ gf_exp[i] = gf_exp[i - 1] << 1;
+ gf_log[gf_exp[i]] = i;
+ }
+ /*
+ * log(0) is not defined, so use a special value
+ */
+ gf_log[0] = GF_SIZE ;
+ /* set the extended gf_exp values for fast multiply */
+ for (i = 0 ; i < GF_SIZE ; i++)
+ gf_exp[i + GF_SIZE] = gf_exp[i] ;
+
+ /*
+ * again special cases. 0 has no inverse. This used to
+ * be initialized to GF_SIZE, but it should make no difference
+ * since noone is supposed to read from here.
+ */
+ inverse[0] = 0 ;
+ inverse[1] = 1;
+ for (i=2; i<=GF_SIZE; i++)
+ inverse[i] = gf_exp[GF_SIZE-gf_log[i]];
+}
+
+/*
+ * Various linear algebra operations that i use often.
+ */
+
+/*
+ * addmul() computes dst[] = dst[] + c * src[]
+ * This is used often, so better optimize it! Currently the loop is
+ * unrolled 16 times, a good value for 486 and pentium-class machines.
+ * The case c=0 is also optimized, whereas c=1 is not. These
+ * calls are unfrequent in my typical apps so I did not bother.
+ *
+ * Note that gcc on
+ */
+#define addmul(dst, src, c, sz) \
+ if (c != 0) addmul1(dst, src, c, sz)
+
+#define UNROLL 16 /* 1, 4, 8, 16 */
+static void
+addmul1(gf *dst1, gf *src1, gf c, int sz)
+{
+ USE_GF_MULC ;
+ register gf *dst = dst1, *src = src1 ;
+ gf *lim = &dst[sz - UNROLL + 1] ;
+
+ GF_MULC0(c) ;
+
+#if (UNROLL > 1) /* unrolling by 8/16 is quite effective on the pentium */
+ for (; dst < lim ; dst += UNROLL, src += UNROLL ) {
+ GF_ADDMULC( dst[0] , src[0] );
+ GF_ADDMULC( dst[1] , src[1] );
+ GF_ADDMULC( dst[2] , src[2] );
+ GF_ADDMULC( dst[3] , src[3] );
+#if (UNROLL > 4)
+ GF_ADDMULC( dst[4] , src[4] );
+ GF_ADDMULC( dst[5] , src[5] );
+ GF_ADDMULC( dst[6] , src[6] );
+ GF_ADDMULC( dst[7] , src[7] );
+#endif
+#if (UNROLL > 8)
+ GF_ADDMULC( dst[8] , src[8] );
+ GF_ADDMULC( dst[9] , src[9] );
+ GF_ADDMULC( dst[10] , src[10] );
+ GF_ADDMULC( dst[11] , src[11] );
+ GF_ADDMULC( dst[12] , src[12] );
+ GF_ADDMULC( dst[13] , src[13] );
+ GF_ADDMULC( dst[14] , src[14] );
+ GF_ADDMULC( dst[15] , src[15] );
+#endif
+ }
+#endif
+ lim += UNROLL - 1 ;
+ for (; dst < lim; dst++, src++ ) /* final components */
+ GF_ADDMULC( *dst , *src );
+}
+
+/*
+ * computes C = AB where A is n*k, B is k*m, C is n*m
+ */
+static void
+matmul(gf *a, gf *b, gf *c, int n, int k, int m)
+{
+ int row, col, i ;
+
+ for (row = 0; row < n ; row++) {
+ for (col = 0; col < m ; col++) {
+ gf *pa = &a[ row * k ];
+ gf *pb = &b[ col ];
+ gf acc = 0 ;
+ for (i = 0; i < k ; i++, pa++, pb += m )
+ acc ^= gf_mul( *pa, *pb ) ;
+ c[ row * m + col ] = acc ;
+ }
+ }
+}
+
+#ifdef DEBUG
+/*
+ * returns 1 if the square matrix is identiy
+ * (only for test)
+ */
+static int
+is_identity(gf *m, int k)
+{
+ int row, col ;
+ for (row=0; row<k; row++)
+ for (col=0; col<k; col++)
+ if ( (row==col && *m != 1) ||
+ (row!=col && *m != 0) )
+ return 0 ;
+ else
+ m++ ;
+ return 1 ;
+}
+#endif /* debug */
+
+/*
+ * invert_mat() takes a matrix and produces its inverse
+ * k is the size of the matrix.
+ * (Gauss-Jordan, adapted from Numerical Recipes in C)
+ * Return non-zero if singular.
+ */
+DEB( int pivloops=0; int pivswaps=0 ; /* diagnostic */)
+static int
+invert_mat(gf *src, int k)
+{
+ gf c, *p ;
+ int irow, icol, row, col, i, ix ;
+
+ int error = 1 ;
+ int *indxc = my_malloc(k*sizeof(int), "indxc");
+ int *indxr = my_malloc(k*sizeof(int), "indxr");
+ int *ipiv = my_malloc(k*sizeof(int), "ipiv");
+ gf *id_row = NEW_GF_MATRIX(1, k);
+ gf *temp_row = NEW_GF_MATRIX(1, k);
+
+ bzero(id_row, k*sizeof(gf));
+ DEB( pivloops=0; pivswaps=0 ; /* diagnostic */ )
+ /*
+ * ipiv marks elements already used as pivots.
+ */
+ for (i = 0; i < k ; i++)
+ ipiv[i] = 0 ;
+
+ for (col = 0; col < k ; col++) {
+ gf *pivot_row ;
+ /*
+ * Zeroing column 'col', look for a non-zero element.
+ * First try on the diagonal, if it fails, look elsewhere.
+ */
+ irow = icol = -1 ;
+ if (ipiv[col] != 1 && src[col*k + col] != 0) {
+ irow = col ;
+ icol = col ;
+ goto found_piv ;
+ }
+ for (row = 0 ; row < k ; row++) {
+ if (ipiv[row] != 1) {
+ for (ix = 0 ; ix < k ; ix++) {
+ DEB( pivloops++ ; )
+ if (ipiv[ix] == 0) {
+ if (src[row*k + ix] != 0) {
+ irow = row ;
+ icol = ix ;
+ goto found_piv ;
+ }
+ } else if (ipiv[ix] > 1) {
+ fprintf(stderr, "singular matrix\n");
+ goto fail ;
+ }
+ }
+ }
+ }
+ if (icol == -1) {
+ fprintf(stderr, "XXX pivot not found!\n");
+ goto fail ;
+ }
+found_piv:
+ ++(ipiv[icol]) ;
+ /*
+ * swap rows irow and icol, so afterwards the diagonal
+ * element will be correct. Rarely done, not worth
+ * optimizing.
+ */
+ if (irow != icol) {
+ for (ix = 0 ; ix < k ; ix++ ) {
+ SWAP( src[irow*k + ix], src[icol*k + ix], gf) ;
+ }
+ }
+ indxr[col] = irow ;
+ indxc[col] = icol ;
+ pivot_row = &src[icol*k] ;
+ c = pivot_row[icol] ;
+ if (c == 0) {
+ fprintf(stderr, "singular matrix 2\n");
+ goto fail ;
+ }
+ if (c != 1 ) { /* otherwhise this is a NOP */
+ /*
+ * this is done often , but optimizing is not so
+ * fruitful, at least in the obvious ways (unrolling)
+ */
+ DEB( pivswaps++ ; )
+ c = inverse[ c ] ;
+ pivot_row[icol] = 1 ;
+ for (ix = 0 ; ix < k ; ix++ )
+ pivot_row[ix] = gf_mul(c, pivot_row[ix] );
+ }
+ /*
+ * from all rows, remove multiples of the selected row
+ * to zero the relevant entry (in fact, the entry is not zero
+ * because we know it must be zero).
+ * (Here, if we know that the pivot_row is the identity,
+ * we can optimize the addmul).
+ */
+ id_row[icol] = 1;
+ if (bcmp(pivot_row, id_row, k*sizeof(gf)) != 0) {
+ for (p = src, ix = 0 ; ix < k ; ix++, p += k ) {
+ if (ix != icol) {
+ c = p[icol] ;
+ p[icol] = 0 ;
+ addmul(p, pivot_row, c, k );
+ }
+ }
+ }
+ id_row[icol] = 0;
+ } /* done all columns */
+ for (col = k-1 ; col >= 0 ; col-- ) {
+ if (indxr[col] <0 || indxr[col] >= k)
+ fprintf(stderr, "AARGH, indxr[col] %d\n", indxr[col]);
+ else if (indxc[col] <0 || indxc[col] >= k)
+ fprintf(stderr, "AARGH, indxc[col] %d\n", indxc[col]);
+ else
+ if (indxr[col] != indxc[col] ) {
+ for (row = 0 ; row < k ; row++ ) {
+ SWAP( src[row*k + indxr[col]], src[row*k + indxc[col]], gf) ;
+ }
+ }
+ }
+ error = 0 ;
+fail:
+ free(indxc);
+ free(indxr);
+ free(ipiv);
+ free(id_row);
+ free(temp_row);
+ return error ;
+}
+
+/*
+ * fast code for inverting a vandermonde matrix.
+ * XXX NOTE: It assumes that the matrix
+ * is not singular and _IS_ a vandermonde matrix. Only uses
+ * the second column of the matrix, containing the p_i's.
+ *
+ * Algorithm borrowed from "Numerical recipes in C" -- sec.2.8, but
+ * largely revised for my purposes.
+ * p = coefficients of the matrix (p_i)
+ * q = values of the polynomial (known)
+ */
+
+int
+invert_vdm(gf *src, int k)
+{
+ int i, j, row, col ;
+ gf *b, *c, *p;
+ gf t, xx ;
+
+ if (k == 1) /* degenerate case, matrix must be p^0 = 1 */
+ return 0 ;
+ /*
+ * c holds the coefficient of P(x) = Prod (x - p_i), i=0..k-1
+ * b holds the coefficient for the matrix inversion
+ */
+ c = NEW_GF_MATRIX(1, k);
+ b = NEW_GF_MATRIX(1, k);
+
+ p = NEW_GF_MATRIX(1, k);
+
+ for ( j=1, i = 0 ; i < k ; i++, j+=k ) {
+ c[i] = 0 ;
+ p[i] = src[j] ; /* p[i] */
+ }
+ /*
+ * construct coeffs. recursively. We know c[k] = 1 (implicit)
+ * and start P_0 = x - p_0, then at each stage multiply by
+ * x - p_i generating P_i = x P_{i-1} - p_i P_{i-1}
+ * After k steps we are done.
+ */
+ c[k-1] = p[0] ; /* really -p(0), but x = -x in GF(2^m) */
+ for (i = 1 ; i < k ; i++ ) {
+ gf p_i = p[i] ; /* see above comment */
+ for (j = k-1 - ( i - 1 ) ; j < k-1 ; j++ )
+ c[j] ^= gf_mul( p_i, c[j+1] ) ;
+ c[k-1] ^= p_i ;
+ }
+
+ for (row = 0 ; row < k ; row++ ) {
+ /*
+ * synthetic division etc.
+ */
+ xx = p[row] ;
+ t = 1 ;
+ b[k-1] = 1 ; /* this is in fact c[k] */
+ for (i = k-2 ; i >= 0 ; i-- ) {
+ b[i] = c[i+1] ^ gf_mul(xx, b[i+1]) ;
+ t = gf_mul(xx, t) ^ b[i] ;
+ }
+ for (col = 0 ; col < k ; col++ )
+ src[col*k + row] = gf_mul(inverse[t], b[col] );
+ }
+ free(c) ;
+ free(b) ;
+ free(p) ;
+ return 0 ;
+}
+
+static int fec_initialized = 0 ;
+static void
+init_fec()
+{
+ TICK(ticks[0]);
+ generate_gf();
+ TOCK(ticks[0]);
+ DDB(fprintf(stderr, "generate_gf took %ldus\n", ticks[0]);)
+ TICK(ticks[0]);
+ init_mul_table();
+ TOCK(ticks[0]);
+ DDB(fprintf(stderr, "init_mul_table took %ldus\n", ticks[0]);)
+ fec_initialized = 1 ;
+}
+
+/*
+ * This section contains the proper FEC encoding/decoding routines.
+ * The encoding matrix is computed starting with a Vandermonde matrix,
+ * and then transforming it into a systematic matrix.
+ */
+
+#define FEC_MAGIC 0xFECC0DEC
+
+struct fec_parms {
+ u_long magic ;
+ int k, n ; /* parameters of the code */
+ gf *enc_matrix ;
+} ;
+
+void
+fec_free(struct fec_parms *p)
+{
+ if (p==NULL ||
+ p->magic != ( ( (FEC_MAGIC ^ p->k) ^ p->n) ^ (int)(p->enc_matrix)) ) {
+ fprintf(stderr, "bad parameters to fec_free\n");
+ return ;
+ }
+ free(p->enc_matrix);
+ free(p);
+}
+
+/*
+ * create a new encoder, returning a descriptor. This contains k,n and
+ * the encoding matrix.
+ */
+struct fec_parms *
+fec_new(int k, int n)
+{
+ int row, col ;
+ gf *p, *tmp_m ;
+
+ struct fec_parms *retval ;
+
+ if (fec_initialized == 0)
+ init_fec();
+
+ if (k > GF_SIZE + 1 || n > GF_SIZE + 1 || k > n ) {
+ fprintf(stderr, "Invalid parameters k %d n %d GF_SIZE %d\n",
+ k, n, GF_SIZE );
+ return NULL ;
+ }
+ retval = my_malloc(sizeof(struct fec_parms), "new_code");
+ retval->k = k ;
+ retval->n = n ;
+ retval->enc_matrix = NEW_GF_MATRIX(n, k);
+ retval->magic = ( ( FEC_MAGIC ^ k) ^ n) ^ (int)(retval->enc_matrix) ;
+ tmp_m = NEW_GF_MATRIX(n, k);
+ /*
+ * fill the matrix with powers of field elements, starting from 0.
+ * The first row is special, cannot be computed with exp. table.
+ */
+ tmp_m[0] = 1 ;
+ for (col = 1; col < k ; col++)
+ tmp_m[col] = 0 ;
+ for (p = tmp_m + k, row = 0; row < n-1 ; row++, p += k) {
+ for ( col = 0 ; col < k ; col ++ )
+ p[col] = gf_exp[modnn(row*col)];
+ }
+
+ /*
+ * quick code to build systematic matrix: invert the top
+ * k*k vandermonde matrix, multiply right the bottom n-k rows
+ * by the inverse, and construct the identity matrix at the top.
+ */
+ TICK(ticks[3]);
+ invert_vdm(tmp_m, k); /* much faster than invert_mat */
+ matmul(tmp_m + k*k, tmp_m, retval->enc_matrix + k*k, n - k, k, k);
+ /*
+ * the upper matrix is I so do not bother with a slow multiply
+ */
+ bzero(retval->enc_matrix, k*k*sizeof(gf) );
+ for (p = retval->enc_matrix, col = 0 ; col < k ; col++, p += k+1 )
+ *p = 1 ;
+ free(tmp_m);
+ TOCK(ticks[3]);
+
+ DDB(fprintf(stderr, "--- %ld us to build encoding matrix\n",
+ ticks[3]);)
+ DEB(pr_matrix(retval->enc_matrix, n, k, "encoding_matrix");)
+ return retval ;
+}
+
+/*
+ * fec_encode accepts as input pointers to n data packets of size sz,
+ * and produces as output a packet pointed to by fec, computed
+ * with index "index".
+ */
+void
+fec_encode(struct fec_parms *code, gf *src[], gf *fec, int index, int sz)
+{
+ int i, k = code->k ;
+ gf *p ;
+
+ if (GF_BITS > 8)
+ sz /= 2 ;
+
+ if (index < k)
+ bcopy(src[index], fec, sz*sizeof(gf) ) ;
+ else if (index < code->n) {
+ p = &(code->enc_matrix[index*k] );
+ bzero(fec, sz*sizeof(gf));
+ for (i = 0; i < k ; i++)
+ addmul(fec, src[i], p[i], sz ) ;
+ } else
+ fprintf(stderr, "Invalid index %d (max %d)\n",
+ index, code->n - 1 );
+}
+
+/*
+ * shuffle move src packets in their position
+ */
+static int
+shuffle(gf *pkt[], int index[], int k)
+{
+ int i;
+
+ for ( i = 0 ; i < k ; ) {
+ if (index[i] >= k || index[i] == i)
+ i++ ;
+ else {
+ /*
+ * put pkt in the right position (first check for conflicts).
+ */
+ int c = index[i] ;
+
+ if (index[c] == c) {
+ DEB(fprintf(stderr, "\nshuffle, error at %d\n", i);)
+ return 1 ;
+ }
+ SWAP(index[i], index[c], int) ;
+ SWAP(pkt[i], pkt[c], gf *) ;
+ }
+ }
+ DEB( /* just test that it works... */
+ for ( i = 0 ; i < k ; i++ ) {
+ if (index[i] < k && index[i] != i) {
+ fprintf(stderr, "shuffle: after\n");
+ for (i=0; i<k ; i++) fprintf(stderr, "%3d ", index[i]);
+ fprintf(stderr, "\n");
+ return 1 ;
+ }
+ }
+ )
+ return 0 ;
+}
+
+/*
+ * build_decode_matrix constructs the encoding matrix given the
+ * indexes. The matrix must be already allocated as
+ * a vector of k*k elements, in row-major order
+ */
+static gf *
+build_decode_matrix(struct fec_parms *code, gf *pkt[], int index[])
+{
+ int i , k = code->k ;
+ gf *p, *matrix = NEW_GF_MATRIX(k, k);
+
+ TICK(ticks[9]);
+ for (i = 0, p = matrix ; i < k ; i++, p += k ) {
+#if 1 /* this is simply an optimization, not very useful indeed */
+ if (index[i] < k) {
+ bzero(p, k*sizeof(gf) );
+ p[i] = 1 ;
+ } else
+#endif
+ if (index[i] < code->n )
+ bcopy( &(code->enc_matrix[index[i]*k]), p, k*sizeof(gf) );
+ else {
+ fprintf(stderr, "decode: invalid index %d (max %d)\n",
+ index[i], code->n - 1 );
+ free(matrix) ;
+ return NULL ;
+ }
+ }
+ TICK(ticks[9]);
+ if (invert_mat(matrix, k)) {
+ free(matrix);
+ matrix = NULL ;
+ }
+ TOCK(ticks[9]);
+ return matrix ;
+}
+
+/*
+ * fec_decode receives as input a vector of packets, the indexes of
+ * packets, and produces the correct vector as output.
+ *
+ * Input:
+ * code: pointer to code descriptor
+ * pkt: pointers to received packets. They are modified
+ * to store the output packets (in place)
+ * index: pointer to packet indexes (modified)
+ * sz: size of each packet
+ */
+int
+fec_decode(struct fec_parms *code, gf *pkt[], int index[], int sz)
+{
+ gf *m_dec ;
+ gf **new_pkt ;
+ int row, col , k = code->k ;
+
+ if (GF_BITS > 8)
+ sz /= 2 ;
+
+ if (shuffle(pkt, index, k)) /* error if true */
+ return 1 ;
+ m_dec = build_decode_matrix(code, pkt, index);
+
+ if (m_dec == NULL)
+ return 1 ; /* error */
+ /*
+ * do the actual decoding
+ */
+ new_pkt = my_malloc (k * sizeof (gf * ), "new pkt pointers" );
+ for (row = 0 ; row < k ; row++ ) {
+ if (index[row] >= k) {
+ new_pkt[row] = my_malloc (sz * sizeof (gf), "new pkt buffer" );
+ bzero(new_pkt[row], sz * sizeof(gf) ) ;
+ for (col = 0 ; col < k ; col++ )
+ addmul(new_pkt[row], pkt[col], m_dec[row*k + col], sz) ;
+ }
+ }
+ /*
+ * move pkts to their final destination
+ */
+ for (row = 0 ; row < k ; row++ ) {
+ if (index[row] >= k) {
+ bcopy(new_pkt[row], pkt[row], sz*sizeof(gf));
+ free(new_pkt[row]);
+ }
+ }
+ free(new_pkt);
+ free(m_dec);
+
+ return 0;
+}
+
+/*********** end of FEC code -- beginning of test code ************/
+
+#if (TEST || DEBUG)
+void
+test_gf()
+{
+ int i ;
+ /*
+ * test gf tables. Sufficiently tested...
+ */
+ for (i=0; i<= GF_SIZE; i++) {
+ if (gf_exp[gf_log[i]] != i)
+ fprintf(stderr, "bad exp/log i %d log %d exp(log) %d\n",
+ i, gf_log[i], gf_exp[gf_log[i]]);
+
+ if (i != 0 && gf_mul(i, inverse[i]) != 1)
+ fprintf(stderr, "bad mul/inv i %d inv %d i*inv(i) %d\n",
+ i, inverse[i], gf_mul(i, inverse[i]) );
+ if (gf_mul(0,i) != 0)
+ fprintf(stderr, "bad mul table 0,%d\n",i);
+ if (gf_mul(i,0) != 0)
+ fprintf(stderr, "bad mul table %d,0\n",i);
+ }
+}
+#endif /* TEST */
int main(int argc, char **argv)
{
- struct sockaddr_storage server_addr;
- socklen_t server_addrlen = sizeof(server_addr);
struct addrinfo *ai;
struct addrinfo hints;
struct addrinfo *runp;
int ret;
int sock;
- struct image_pkt pktbuf;
size_t len;
int flfd;
struct mtd_info_user meminfo;
unsigned char *eb_buf;
unsigned char *blockmap = NULL;
- unsigned char *subblockmap;
int nr_blocks = 0;
- int nr_subblocks = 0;
+ int *pkt_indices;
+ unsigned char **pkts;
+ int nr_pkts = 0;
int pkts_per_block;
int block_nr = -1;
uint32_t image_crc;
uint32_t blocks_received = 0;
- uint32_t block_ofs;
loff_t mtdoffset = 0;
int *stats;
int badcrcs = 0;
int duplicates = 0;
- int missing = -1;
int file_mode = 0;
+ struct fec_parms *fec;
+ int i;
if (argc != 4) {
fprintf(stderr, "usage: %s <host> <port> <mtddev>\n",
pkts_per_block = (meminfo.erasesize + PKT_SIZE - 1) / PKT_SIZE;
- stats = malloc(pkts_per_block + 1);
- if (!stats) {
- fprintf(stderr, "No memory for statistics\n");
- exit(1);
- }
- memset(stats, 0, sizeof(int) * (pkts_per_block + 1));
-
eb_buf = malloc(pkts_per_block * PKT_SIZE);
if (!eb_buf) {
fprintf(stderr, "No memory for eraseblock buffer\n");
exit(1);
}
- memset(eb_buf, 0, pkts_per_block * PKT_SIZE);
- subblockmap = malloc(pkts_per_block + 1);
- if (!subblockmap) {
- fprintf(stderr, "No memory for subblock map\n");
+ pkt_indices = malloc(sizeof(int) * pkts_per_block);
+ if (!pkt_indices) {
+ fprintf(stderr, "No memory for packet indices\n");
+ exit(1);
+ }
+ memset(pkt_indices, 0, sizeof(int) * pkts_per_block);
+
+ pkts = malloc(sizeof(unsigned char *) * pkts_per_block);
+ if (!pkts) {
+ fprintf(stderr, "No memory for packet pointers\n");
exit(1);
}
- memset(subblockmap, 0, pkts_per_block + 1);
+ for (i=0; i<pkts_per_block; i++) {
+ pkts[i] = malloc(sizeof(struct image_pkt_hdr) + PKT_SIZE);
+ if (!pkts[i]) {
+ printf("No memory for packets\n");
+ exit(1);
+ }
+ pkts[i] += sizeof(struct image_pkt_hdr);
+ }
memset(&hints, 0, sizeof(hints));
hints.ai_flags = AI_ADDRCONFIG;
close(sock);
continue;
}
- } else printf("not multicast?\n");
+ }
if (bind(sock, runp->ai_addr, runp->ai_addrlen)) {
perror("bind");
close(sock);
if (!runp)
exit(1);
- while ((len = read(sock, &pktbuf, sizeof(pktbuf))) >= 0) {
- if (len < sizeof(pktbuf.hdr)) {
- fprintf(stderr, "Short read %d bytes\n", len);
- continue;
+ while (1) {
+ struct image_pkt *thispkt;
+
+ if (nr_pkts < pkts_per_block)
+ thispkt = (void *)(pkts[nr_pkts] - sizeof(struct image_pkt_hdr));
+ else
+ thispkt = (void *)(pkts[0] - sizeof(struct image_pkt_hdr));
+
+ len = read(sock, thispkt, sizeof(*thispkt));
+
+ if (len < 0) {
+ perror("read socket");
+ break;
}
- if (len != sizeof(pktbuf.hdr) + ntohl(pktbuf.hdr.thislen)) {
- fprintf(stderr, "Wrong length %d bytes (expected %d+%d)\n",
- len, sizeof(pktbuf.hdr), ntohl(pktbuf.hdr.thislen));
+ if (len < sizeof(*thispkt)) {
+ fprintf(stderr, "Wrong length %d bytes (expected %d)\n",
+ len, sizeof(*thispkt));
continue;
}
- /* Holds _data_ length */
- len -= sizeof(pktbuf.hdr);
-
if (!blockmap) {
- image_crc = pktbuf.hdr.totcrc;
- if (meminfo.erasesize != ntohl(pktbuf.hdr.blocksize)) {
+ image_crc = thispkt->hdr.totcrc;
+ if (meminfo.erasesize != ntohl(thispkt->hdr.blocksize)) {
fprintf(stderr, "Erasesize mismatch (0x%x not 0x%x)\n",
- ntohl(pktbuf.hdr.blocksize), meminfo.erasesize);
+ ntohl(thispkt->hdr.blocksize), meminfo.erasesize);
exit(1);
}
- nr_blocks = ntohl(pktbuf.hdr.nr_blocks);
- nr_subblocks = pkts_per_block + 2;
+ nr_blocks = ntohl(thispkt->hdr.nr_blocks);
+ nr_pkts = 0;
+
+ fec = fec_new(pkts_per_block, ntohs(thispkt->hdr.nr_pkts));
+
blockmap = malloc(nr_blocks);
if (!blockmap) {
fprintf(stderr, "No memory for block map\n");
exit(1);
}
memset(blockmap, 0, nr_blocks);
+ stats = malloc(sizeof(int) * (ntohs(thispkt->hdr.nr_pkts) + 1));
+ if (!stats) {
+ fprintf(stderr, "No memory for statistics\n");
+ exit(1);
+ }
+ memset(stats, 0, sizeof(int) * (ntohs(thispkt->hdr.nr_pkts) + 1));
}
- if (image_crc != pktbuf.hdr.totcrc) {
+ if (image_crc != thispkt->hdr.totcrc) {
fprintf(stderr, "Image CRC changed from 0x%x to 0x%x. Aborting\n",
- ntohl(image_crc), ntohl(pktbuf.hdr.totcrc));
+ ntohl(image_crc), ntohl(thispkt->hdr.totcrc));
exit(1);
}
- if (ntohl(pktbuf.hdr.block_nr) != block_nr) {
+ if (ntohl(thispkt->hdr.block_nr) != block_nr) {
/* Hm, new block */
- if (nr_subblocks < pkts_per_block &&
- block_nr != -1)
- printf("Lost image block at %08x with only %d/%d packets\n",
- block_nr * meminfo.erasesize, nr_subblocks,
- pkts_per_block + 1);
+ if (block_nr != -1) {
+ if (!blockmap[block_nr]) {
+ printf("Lost image block %08x with only %d/%d (%d) packets\n",
+ block_nr * meminfo.erasesize, nr_pkts, pkts_per_block,
+ ntohs(thispkt->hdr.nr_pkts));
+ }
+ if (blockmap[block_nr] < 2) {
+ stats[nr_pkts]++;
+ if (blockmap[block_nr]) {
+ if (file_mode)
+ printf(" with %d/%d (%d) packets\n",
+ nr_pkts, pkts_per_block,
+ ntohs(thispkt->hdr.nr_pkts));
+ blockmap[block_nr] = 2;
+ }
+ }
+ }
+ /* Put this packet first */
+ if (nr_pkts != 0 && nr_pkts < pkts_per_block) {
+ unsigned char *tmp = pkts[0];
+ pkts[0] = pkts[nr_pkts];
+ pkts[nr_pkts] = tmp;
+ }
+ nr_pkts = 0;
- if (nr_subblocks < pkts_per_block + 2)
- stats[nr_subblocks]++;
+ block_nr = ntohl(thispkt->hdr.block_nr);
- nr_subblocks = 0;
- missing = -1;
- memset(subblockmap, 0, pkts_per_block + 1);
- block_nr = ntohl(pktbuf.hdr.block_nr);
if (block_nr > nr_blocks) {
fprintf(stderr, "Erroneous block_nr %d (> %d)\n",
block_nr, nr_blocks);
if (blockmap[block_nr]) {
printf("Discard chunk at 0x%08x for already-flashed eraseblock (%d to go)\n",
block_nr * meminfo.erasesize, nr_blocks - blocks_received);
- nr_subblocks = pkts_per_block + 2;
continue;
}
}
- if (nr_subblocks == pkts_per_block) {
+ if (nr_pkts >= pkts_per_block) {
/* We have a parity block but we didn't need it */
- nr_subblocks++;
+ nr_pkts++;
continue;
}
if (blockmap[block_nr])
continue;
- block_ofs = ntohl(pktbuf.hdr.block_ofs);
- if (block_ofs == meminfo.erasesize)
- block_ofs = PKT_SIZE * pkts_per_block;
-
- if (len != PKT_SIZE && len + block_ofs != meminfo.erasesize) {
- fprintf(stderr, "Bogus packet size 0x%x (expected 0x%x)\n",
- ntohl(pktbuf.hdr.thislen),
- min(PKT_SIZE, meminfo.erasesize - block_ofs));
- exit(1);
- }
+ for (i=0; i < nr_pkts; i++) {
+ if (pkt_indices[i] == ntohs(thispkt->hdr.pkt_nr)) {
+ printf("Discarding duplicate packet at %08x pkt %d\n",
+ block_nr * meminfo.erasesize, pkt_indices[i]);
+ duplicates++;
+ break;
+ }
+ } /* And if we broke out, skip the packet... */
+ if (i < nr_pkts)
+ continue;
- if (crc32(-1, pktbuf.data, len) != ntohl(pktbuf.hdr.thiscrc)) {
- printf("Discard chunk %08x with bad CRC (%08x not %08x)\n",
- block_nr * meminfo.erasesize + block_ofs,
- crc32(-1, pktbuf.data, pktbuf.hdr.thislen),
- ntohl(pktbuf.hdr.thiscrc));
+ if (crc32(-1, thispkt->data, PKT_SIZE) != ntohl(thispkt->hdr.thiscrc)) {
+ printf("Discard %08x pkt %d with bad CRC (%08x not %08x)\n",
+ block_nr * meminfo.erasesize, ntohs(thispkt->hdr.pkt_nr),
+ crc32(-1, thispkt->data, PKT_SIZE),
+ ntohl(thispkt->hdr.thiscrc));
badcrcs++;
continue;
}
- if (subblockmap[block_ofs / PKT_SIZE]) {
- printf("Discarding duplicate packet at %08x\n",
- block_nr * meminfo.erasesize + block_ofs);
- duplicates++;
- continue;
- }
- subblockmap[block_ofs / PKT_SIZE] = 1;
- nr_subblocks++;
- if (block_ofs < meminfo.erasesize) {
- /* Normal data packet */
- memcpy(eb_buf + block_ofs, pktbuf.data, len);
-// printf("Received data block at %08x\n", block_nr * meminfo.erasesize + block_ofs);
- } else {
- /* Parity block */
- int i;
- /* If we don't have enough to recover, skip */
- if (nr_subblocks < pkts_per_block)
- continue;
+ pkt_indices[nr_pkts] = ntohs(thispkt->hdr.pkt_nr);
+ nr_pkts++;
- for (i = 0; i<pkts_per_block; i++) {
- if (subblockmap[i]) {
- int j;
- for (j=0; j<PKT_SIZE; j++)
- pktbuf.data[j] ^= eb_buf[i*PKT_SIZE + j];
- } else
- missing = i;
- }
+ if (nr_pkts == pkts_per_block) {
- if (missing == -1) {
- fprintf(stderr, "dwmw2 is stupid\n");
+ if (fec_decode(fec, pkts, pkt_indices, PKT_SIZE)) {
+ /* Eep. This cannot happen */
+ printf("The world is broken. fec_decode() returned error\n");
exit(1);
}
-// printf("Recover missing packet at %08x from parity\n",
-// block_nr * meminfo.erasesize + missing * PKT_SIZE);
- memcpy(eb_buf + (missing * PKT_SIZE), pktbuf.data, PKT_SIZE);
- }
-
- if (nr_subblocks == pkts_per_block) {
-
blockmap[block_nr] = 1;
blocks_received++;
+ /* Put data into order in eb_buf */
+ for (i=0; i < pkts_per_block; i++)
+ memcpy(eb_buf + (i * PKT_SIZE), pkts[i], PKT_SIZE);
+
+ if (crc32(-1, eb_buf, meminfo.erasesize) != ntohl(thispkt->hdr.block_crc)) {
+ printf("FEC error. CRC %08x != %08x\n",
+ crc32(-1, eb_buf, meminfo.erasesize),
+ ntohl(thispkt->hdr.block_crc));
+ *(int *)0 = 0;
+ exit(1);
+ }
if (file_mode) {
- printf("Received image block %08x%s (%d/%d)\n",
+ printf("Received image block %08x (%d/%d)",
block_nr * meminfo.erasesize,
- (missing==-1)?"":" (parity)",
blocks_received, nr_blocks);
pwrite(flfd, eb_buf, meminfo.erasesize, block_nr * meminfo.erasesize);
} else {
mtdoffset += meminfo.erasesize;
goto again;
}
- printf("Wrote image block %08x (%d/%d) to flash offset %08x%s\n",
+ printf("Wrote image block %08x (%d/%d) to flash offset %08x\n",
block_nr * meminfo.erasesize,
blocks_received, nr_blocks,
- (uint32_t)mtdoffset,
- (missing==-1)?"":" (parity)");
+ (uint32_t)mtdoffset);
mtdoffset += meminfo.erasesize;
}
if (!(blocks_received%100) || blocks_received == nr_blocks) {
int i, printed = 0;
- for (i=0; i <= pkts_per_block + 1; i++) {
+ printf("\n");
+ for (i=0; i <= ntohs(thispkt->hdr.nr_pkts); i++) {
if (printed || stats[i]) {
printf("Number of blocks with %d packets received: %d\n",
i, stats[i]);
+#define _POSIX_C_SOURCE 199309
+
+#include <time.h>
+
#include <errno.h>
#include <error.h>
#include <netdb.h>
#include "mcast_image.h"
int tx_rate = 80000;
-int pkt_delay = 12500 * PKT_SIZE / 1024;
+int pkt_delay;
+
+#undef RANDOMDROP
int main(int argc, char **argv)
{
struct stat st;
int writeerrors = 0;
uint32_t erasesize;
- unsigned char parbuf[PKT_SIZE];
unsigned char *image, *blockptr;
uint32_t block_nr;
- uint32_t block_ofs;
int nr_blocks;
- uint32_t droppoint = -1;
struct timeval then, now, nextpkt;
long time_msecs;
+ unsigned char **src_pkts;
+ unsigned char last_src_pkt[PKT_SIZE];
+ int pkts_extra = 6;
+ int pkts_per_block;
+ struct fec_parms *fec;
- if (argc == 6) {
- tx_rate = atol(argv[5]) * 1024;
+ if (argc == 7) {
+ tx_rate = atol(argv[6]) * 1024;
if (tx_rate < PKT_SIZE || tx_rate > 20000000) {
fprintf(stderr, "Bogus TX rate %d KiB/s\n", tx_rate);
exit(1);
}
+ argc = 6;
+ }
+ if (argc == 6) {
+ pkts_extra = atol(argv[5]);
+ if (pkts_extra < 0 || pkts_extra > 200) {
+ fprintf(stderr, "Bogus redundancy %d packets\n", pkts_extra);
+ exit(1);
+ }
argc = 5;
}
if (argc != 5) {
- fprintf(stderr, "usage: %s <host> <port> <image> <erasesize> [<tx_rate>]\n",
+ fprintf(stderr, "usage: %s <host> <port> <image> <erasesize> [<redundancy>] [<tx_rate>]\n",
(strrchr(argv[0], '/')?:argv[0]-1)+1);
exit(1);
}
fprintf(stderr, "erasesize cannot be zero\n");
exit(1);
}
+
+ pkts_per_block = (erasesize + PKT_SIZE - 1) / PKT_SIZE;
+ src_pkts = malloc(pkts_per_block * sizeof(unsigned char *));
+ if (!src_pkts) {
+ fprintf(stderr, "Failed to allocate memory for packet pointers\n");
+ exit(1);
+ }
+ /* We have to pad it with zeroes, so can't use it in-place */
+ src_pkts[pkts_per_block-1] = last_src_pkt;
+
+ fec = fec_new(pkts_per_block, pkts_per_block + pkts_extra);
+ if (!fec) {
+ fprintf(stderr, "Error initialising FEC\n");
+ exit(1);
+ }
+
memset(&hints, 0, sizeof(hints));
hints.ai_flags = AI_ADDRCONFIG;
hints.ai_socktype = SOCK_DGRAM;
pktbuf.hdr.totcrc = htonl(crc32(-1, image, st.st_size));
pktbuf.hdr.nr_blocks = htonl(nr_blocks);
pktbuf.hdr.blocksize = htonl(erasesize);
+ pktbuf.hdr.thislen = htonl(PKT_SIZE);
+ pktbuf.hdr.nr_pkts = htons(pkts_per_block + pkts_extra);
printf("%08x\n", ntohl(pktbuf.hdr.totcrc));
+ again:
+ printf("Image size %ld KiB (%08lx). %d redundant packets per block (%d total)\n"
+ "Data to send %d KiB. Estimated transmit time: %ds\n",
+ (long)st.st_size / 1024, (long) st.st_size, pkts_extra, pkts_extra+pkts_per_block,
+ nr_blocks * PKT_SIZE * (pkts_per_block+pkts_extra) / 1024,
+ nr_blocks * (pkts_per_block+pkts_extra) * pkt_delay / 1000000);
gettimeofday(&then, NULL);
nextpkt = then;
+#ifdef RANDOMDROP
+ srand((unsigned)then.tv_usec);
+ printf("Random seed %u\n", (unsigned)then.tv_usec);
+#endif
blockptr = image;
for (block_nr = 0; block_nr < nr_blocks; block_nr++) {
- int len;
- int dropped = 0;
+ int i;
+ long tosleep;
+
+ blockptr = image + (erasesize * block_nr);
+
+ pktbuf.hdr.block_crc = htonl(crc32(-1, blockptr, erasesize));
+
+ for (i=0; i < pkts_per_block-1; i++)
+ src_pkts[i] = blockptr + (i*PKT_SIZE);
+
+ memcpy(last_src_pkt, blockptr + (i*PKT_SIZE),
+ erasesize - (i * PKT_SIZE));
pktbuf.hdr.block_nr = htonl(block_nr);
- for (block_ofs = 0; block_ofs <= erasesize; block_ofs += len) {
- int i;
+ for (i=0; i < pkts_per_block + pkts_extra; i++) {
+
+ fec_encode(fec, src_pkts, pktbuf.data, i, PKT_SIZE);
- if (block_ofs + PKT_SIZE > erasesize)
- len = erasesize - block_ofs;
- else
- len = PKT_SIZE;
+ printf("\rSending data block %08x packet %3d/%d",
+ block_nr * erasesize, i, pkts_per_block + pkts_extra);
- if (block_ofs == erasesize) {
+ if (block_nr && !i) {
gettimeofday(&now, NULL);
time_msecs = (now.tv_sec - then.tv_sec) * 1000;
time_msecs += ((int)(now.tv_usec - then.tv_usec)) / 1000;
-
- printf("\rSending parity block: %08x (%ld KiB/s) ",
- block_nr * erasesize,
- (block_ofs + (block_nr * (erasesize+sizeof(pktbuf)))) / 1024 * 1000 / time_msecs);
-
- len = PKT_SIZE;
- memcpy(pktbuf.data, parbuf, PKT_SIZE);
- } else {
- if (!block_ofs)
- memcpy(parbuf, blockptr, PKT_SIZE);
- else for (i=0; i < len; i++)
- parbuf[i] ^= blockptr[i];
-
- memcpy(pktbuf.data, blockptr, len);
- printf("\rSending data block at %08x",
- block_nr * erasesize + block_ofs);
- blockptr += len;
+ printf(" (%ld KiB/s) ",
+ (block_nr * sizeof(pktbuf) * (pkts_per_block+pkts_extra))
+ / 1024 * 1000 / time_msecs);
}
fflush(stdout);
- pktbuf.hdr.thislen = htonl(len);
- pktbuf.hdr.block_ofs = htonl(block_ofs);
- pktbuf.hdr.thiscrc = htonl(crc32(-1, pktbuf.data, len));
-
- if (droppoint == block_ofs && !dropped) {
- dropped = 1;
- if (droppoint == 0)
- droppoint = erasesize;
- else if (droppoint == erasesize)
- droppoint = ((erasesize - 1) / PKT_SIZE) * PKT_SIZE;
- else droppoint -= PKT_SIZE;
- printf("\nDropping data block at %08x\n", block_ofs);
+ pktbuf.hdr.pkt_nr = htons(i);
+ pktbuf.hdr.thiscrc = htonl(crc32(-1, pktbuf.data, PKT_SIZE));
+
+#ifdef RANDOMDROP
+ if ((rand() % 1000) < 20) {
+ printf("\nDropping packet %d\n", i+1);
continue;
}
+#endif
+ gettimeofday(&now, NULL);
+#if 1
+ tosleep = nextpkt.tv_usec - now.tv_usec +
+ (1000000 * (nextpkt.tv_sec - now.tv_sec));
- if (write(sock, &pktbuf, sizeof(pktbuf.hdr)+len) < 0) {
- perror("write");
- writeerrors++;
- if (writeerrors > 10) {
- fprintf(stderr, "Too many consecutive write errors\n");
- exit(1);
- }
- } else
- writeerrors = 0;
+ /* We need hrtimers for this to actually work */
+ if (tosleep > 0) {
+ struct timespec req;
- do {
- gettimeofday(&now, NULL);
- } while (now.tv_sec < nextpkt.tv_sec ||
- (now.tv_sec == nextpkt.tv_sec &&
- now.tv_usec < nextpkt.tv_usec));
+ req.tv_nsec = (tosleep % 1000000) * 1000;
+ req.tv_sec = tosleep / 1000000;
- nextpkt.tv_usec = now.tv_usec + pkt_delay;
+ nanosleep(&req, NULL);
+ }
+#else
+ while (now.tv_sec < nextpkt.tv_sec ||
+ (now.tv_sec == nextpkt.tv_sec &&
+ now.tv_usec < nextpkt.tv_usec)) {
+ gettimeofday(&now, NULL);
+ }
+#endif
+ nextpkt.tv_usec += pkt_delay;
if (nextpkt.tv_usec >= 1000000) {
nextpkt.tv_sec += nextpkt.tv_usec / 1000000;
nextpkt.tv_usec %= 1000000;
passed, then we've lost time. Adjust our expected
timings accordingly. */
if (now.tv_usec > (now.tv_usec +
- 1000000 * (nextpkt.tv_sec - now.tv_sec)))
+ 1000000 * (nextpkt.tv_sec - now.tv_sec))) {
nextpkt = now;
+ }
+
+ if (write(sock, &pktbuf, sizeof(pktbuf)) < 0) {
+ perror("write");
+ writeerrors++;
+ if (writeerrors > 10) {
+ fprintf(stderr, "Too many consecutive write errors\n");
+ exit(1);
+ }
+ } else
+ writeerrors = 0;
+
+
}
}
- munmap(image, st.st_size);
- close(rfd);
- close(sock);
gettimeofday(&now, NULL);
time_msecs = (now.tv_sec - then.tv_sec) * 1000;
time_msecs += ((int)(now.tv_usec - then.tv_usec)) / 1000;
printf("\n%d KiB sent in %ldms (%ld KiB/s)\n",
- nr_blocks * (erasesize+sizeof(pktbuf)) / 1024, time_msecs,
- nr_blocks * (erasesize+sizeof(pktbuf)) / 1024 * 1000 / time_msecs);
+ nr_blocks * sizeof(pktbuf) * (pkts_per_block+pkts_extra) / 1024, time_msecs,
+ nr_blocks * sizeof(pktbuf) * (pkts_per_block+pkts_extra) / 1024 * 1000 / time_msecs);
+
+ munmap(image, st.st_size);
+ close(rfd);
+ close(sock);
return 0;
}
projects / mtd-utils.git / commitdiff