#include <netinet/in.h>
#ifdef __sun__
#include <inttypes.h>
#else
#include <stdint.h>
#endif
#include <ctype.h>
#include <errno.h>
#include <string.h>
#include <limits.h>

#include <xalloc.h>
#include "modpost.h"

/*
 * Stolen form Cryptographic API.
 *
 * MD4 Message Digest Algorithm (RFC1320).
 *
 * Implementation derived from Andrew Tridgell and Steve French's
 * CIFS MD4 implementation, and the cryptoapi implementation
 * originally based on the public domain implementation written
 * by Colin Plumb in 1993.
 *
 * Copyright (c) Andrew Tridgell 1997-1998.
 * Modified by Steve French (sfrench@us.ibm.com) 2002
 * Copyright (c) Cryptoapi developers.
 * Copyright (c) 2002 David S. Miller (davem@redhat.com)
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 */
#define MD4_DIGEST_SIZE         16
#define MD4_HMAC_BLOCK_SIZE     64
#define MD4_BLOCK_WORDS         16
#define MD4_HASH_WORDS          4

struct md4_ctx {
        uint32_t hash[MD4_HASH_WORDS];
        uint32_t block[MD4_BLOCK_WORDS];
        uint64_t byte_count;
};

static inline uint32_t lshift(uint32_t x, unsigned int s)
{
        x &= 0xFFFFFFFF;
        return ((x << s) & 0xFFFFFFFF) | (x >> (32 - s));
}

static inline uint32_t F(uint32_t x, uint32_t y, uint32_t z)
{
        return (x & y) | ((~x) & z);
}

static inline uint32_t G(uint32_t x, uint32_t y, uint32_t z)
{
        return (x & y) | (x & z) | (y & z);
}

static inline uint32_t H(uint32_t x, uint32_t y, uint32_t z)
{
        return x ^ y ^ z;
}

#define ROUND1(a,b,c,d,k,s) (a = lshift(a + F(b,c,d) + k, s))
#define ROUND2(a,b,c,d,k,s) (a = lshift(a + G(b,c,d) + k + (uint32_t)0x5A827999,s))
#define ROUND3(a,b,c,d,k,s) (a = lshift(a + H(b,c,d) + k + (uint32_t)0x6ED9EBA1,s))

/* XXX: this stuff can be optimized */
static inline void le32_to_cpu_array(uint32_t *buf, unsigned int words)
{
        while (words--) {
                *buf = ntohl(*buf);
                buf++;
        }
}

static inline void cpu_to_le32_array(uint32_t *buf, unsigned int words)
{
        while (words--) {
                *buf = htonl(*buf);
                buf++;
        }
}

static void md4_transform(uint32_t *hash, uint32_t const *in)
{
        uint32_t a, b, c, d;

        a = hash[0];
        b = hash[1];
        c = hash[2];
        d = hash[3];

        ROUND1(a, b, c, d, in[0], 3);
        ROUND1(d, a, b, c, in[1], 7);
        ROUND1(c, d, a, b, in[2], 11);
        ROUND1(b, c, d, a, in[3], 19);
        ROUND1(a, b, c, d, in[4], 3);
        ROUND1(d, a, b, c, in[5], 7);
        ROUND1(c, d, a, b, in[6], 11);
        ROUND1(b, c, d, a, in[7], 19);
        ROUND1(a, b, c, d, in[8], 3);
        ROUND1(d, a, b, c, in[9], 7);
        ROUND1(c, d, a, b, in[10], 11);
        ROUND1(b, c, d, a, in[11], 19);
        ROUND1(a, b, c, d, in[12], 3);
        ROUND1(d, a, b, c, in[13], 7);
        ROUND1(c, d, a, b, in[14], 11);
        ROUND1(b, c, d, a, in[15], 19);

        ROUND2(a, b, c, d,in[ 0], 3);
        ROUND2(d, a, b, c, in[4], 5);
        ROUND2(c, d, a, b, in[8], 9);
        ROUND2(b, c, d, a, in[12], 13);
        ROUND2(a, b, c, d, in[1], 3);
        ROUND2(d, a, b, c, in[5], 5);
        ROUND2(c, d, a, b, in[9], 9);
        ROUND2(b, c, d, a, in[13], 13);
        ROUND2(a, b, c, d, in[2], 3);
        ROUND2(d, a, b, c, in[6], 5);
        ROUND2(c, d, a, b, in[10], 9);
        ROUND2(b, c, d, a, in[14], 13);
        ROUND2(a, b, c, d, in[3], 3);
        ROUND2(d, a, b, c, in[7], 5);
        ROUND2(c, d, a, b, in[11], 9);
        ROUND2(b, c, d, a, in[15], 13);

        ROUND3(a, b, c, d,in[ 0], 3);
        ROUND3(d, a, b, c, in[8], 9);
        ROUND3(c, d, a, b, in[4], 11);
        ROUND3(b, c, d, a, in[12], 15);
        ROUND3(a, b, c, d, in[2], 3);
        ROUND3(d, a, b, c, in[10], 9);
        ROUND3(c, d, a, b, in[6], 11);
        ROUND3(b, c, d, a, in[14], 15);
        ROUND3(a, b, c, d, in[1], 3);
        ROUND3(d, a, b, c, in[9], 9);
        ROUND3(c, d, a, b, in[5], 11);
        ROUND3(b, c, d, a, in[13], 15);
        ROUND3(a, b, c, d, in[3], 3);
        ROUND3(d, a, b, c, in[11], 9);
        ROUND3(c, d, a, b, in[7], 11);
        ROUND3(b, c, d, a, in[15], 15);

        hash[0] += a;
        hash[1] += b;
        hash[2] += c;
        hash[3] += d;
}

static inline void md4_transform_helper(struct md4_ctx *ctx)
{
        le32_to_cpu_array(ctx->block, ARRAY_SIZE(ctx->block));
        md4_transform(ctx->hash, ctx->block);
}

static void md4_init(struct md4_ctx *mctx)
{
        mctx->hash[0] = 0x67452301;
        mctx->hash[1] = 0xefcdab89;
        mctx->hash[2] = 0x98badcfe;
        mctx->hash[3] = 0x10325476;
        mctx->byte_count = 0;
}

static void md4_update(struct md4_ctx *mctx,
                       const unsigned char *data, unsigned int len)
{
        const uint32_t avail = sizeof(mctx->block) - (mctx->byte_count & 0x3f);

        mctx->byte_count += len;

        if (avail > len) {
                memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
                       data, len);
                return;
        }

        memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
               data, avail);

        md4_transform_helper(mctx);
        data += avail;
        len -= avail;

        while (len >= sizeof(mctx->block)) {
                memcpy(mctx->block, data, sizeof(mctx->block));
                md4_transform_helper(mctx);
                data += sizeof(mctx->block);
                len -= sizeof(mctx->block);
        }

        memcpy(mctx->block, data, len);
}

static void md4_final_ascii(struct md4_ctx *mctx, char *out, unsigned int len)
{
        const unsigned int offset = mctx->byte_count & 0x3f;
        char *p = (char *)mctx->block + offset;
        int padding = 56 - (offset + 1);

        *p++ = 0x80;
        if (padding < 0) {
                memset(p, 0x00, padding + sizeof (uint64_t));
                md4_transform_helper(mctx);
                p = (char *)mctx->block;
                padding = 56;
        }

        memset(p, 0, padding);
        mctx->block[14] = mctx->byte_count << 3;
        mctx->block[15] = mctx->byte_count >> 29;
        le32_to_cpu_array(mctx->block, (sizeof(mctx->block) -
                          sizeof(uint64_t)) / sizeof(uint32_t));
        md4_transform(mctx->hash, mctx->block);
        cpu_to_le32_array(mctx->hash, ARRAY_SIZE(mctx->hash));

        snprintf(out, len, "%08X%08X%08X%08X",
                 mctx->hash[0], mctx->hash[1], mctx->hash[2], mctx->hash[3]);
}

static inline void add_char(unsigned char c, struct md4_ctx *md)
{
        md4_update(md, &c, 1);
}

static int parse_string(const char *file, unsigned long len,
                        struct md4_ctx *md)
{
        unsigned long i;

        add_char(file[0], md);
        for (i = 1; i < len; i++) {
                add_char(file[i], md);
                if (file[i] == '"' && file[i-1] != '\\')
                        break;
        }
        return i;
}

static int parse_comment(const char *file, unsigned long len)
{
        unsigned long i;

        for (i = 2; i < len; i++) {
                if (file[i-1] == '*' && file[i] == '/')
                        break;
        }
        return i;
}

/* FIXME: Handle .s files differently (eg. # starts comments) --RR */
static int parse_file(const char *fname, struct md4_ctx *md)
{
        char *file;
        unsigned long i, len;

        file = read_text_file(fname);
        len = strlen(file);

        for (i = 0; i < len; i++) {
                /* Collapse and ignore \ and CR. */
                if (file[i] == '\\' && (i+1 < len) && file[i+1] == '\n') {
                        i++;
                        continue;
                }

                /* Ignore whitespace */
                if (isspace(file[i]))
                        continue;

                /* Handle strings as whole units */
                if (file[i] == '"') {
                        i += parse_string(file+i, len - i, md);
                        continue;
                }

                /* Comments: ignore */
                if (file[i] == '/' && file[i+1] == '*') {
                        i += parse_comment(file+i, len - i);
                        continue;
                }

                add_char(file[i], md);
        }
        free(file);
        return 1;
}
/* Check whether the file is a static library or not */
static bool is_static_library(const char *objfile)
{
        int len = strlen(objfile);

        return objfile[len - 2] == '.' && objfile[len - 1] == 'a';
}

/* We have dir/file.o.  Open dir/.file.o.cmd, look for source_ and deps_ line
 * to figure out source files. */
static int parse_source_files(const char *objfile, struct md4_ctx *md)
{
        char *cmd, *file, *line, *dir, *pos;
        const char *base;
        int dirlen, ret = 0, check_files = 0;

        cmd = xmalloc(strlen(objfile) + sizeof("..cmd"));

        base = get_basename(objfile);
        dirlen = base - objfile;
        sprintf(cmd, "%.*s.%s.cmd", dirlen, objfile, base);

        dir = xmalloc(dirlen + 1);
        strncpy(dir, objfile, dirlen);
        dir[dirlen] = '\0';

        file = read_text_file(cmd);

        pos = file;

        /* Sum all files in the same dir or subdirs. */
        while ((line = get_line(&pos))) {
                char* p;

                /* trim the leading spaces away */
                while (isspace(*line))
                        line++;
                p = line;

                if (strstarts(line, "source_")) {
                        p = strrchr(line, ' ');
                        if (!p) {
                                warn("malformed line: %s\n", line);
                                goto out_file;
                        }
                        p++;
                        if (!parse_file(p, md)) {
                                warn("could not open %s: %s\n",
                                     p, strerror(errno));
                                goto out_file;
                        }
                        continue;
                }
                if (strstarts(line, "deps_")) {
                        check_files = 1;
                        continue;
                }
                if (!check_files)
                        continue;

                /* Continue until line does not end with '\' */
                if ( *(p + strlen(p)-1) != '\\')
                        break;
                /* Terminate line at first space, to get rid of final ' \' */
                while (*p) {
                        if (isspace(*p)) {
                                *p = '\0';
                                break;
                        }
                        p++;
                }

                /* Check if this file is in same dir as objfile */
                if ((strstr(line, dir)+strlen(dir)-1) == strrchr(line, '/')) {
                        if (!parse_file(line, md)) {
                                warn("could not open %s: %s\n",
                                     line, strerror(errno));
                                goto out_file;
                        }

                }

        }

        /* Everyone parsed OK */
        ret = 1;
out_file:
        free(file);
        free(dir);
        free(cmd);
        return ret;
}

/* Calc and record src checksum. */
void get_src_version(const char *modname, char sum[], unsigned sumlen)
{
        char *buf, *pos;
        struct md4_ctx md;
        char *fname;
        char filelist[PATH_MAX + 1];

        /* objects for a module are listed in the first line of *.mod file. */
        snprintf(filelist, sizeof(filelist), "%s.mod", modname);

        buf = read_text_file(filelist);
        pos = buf;

        md4_init(&md);
        while ((fname = strsep(&pos, "\n"))) {
                if (!*fname)
                        continue;
                if (!(is_static_library(fname)) &&
                                !parse_source_files(fname, &md))
                        goto free;
        }

        md4_final_ascii(&md, sum, sumlen);
free:
        free(buf);
}