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view src/http/v2/ngx_http_v2_huff_encode.c @ 6749:f88a145b093e stable-1.10

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HTTP/2: the "421 Misdirected Request" response (closes #848). Since 4fbef397c753 nginx rejects with the 400 error any attempts of requesting different host over the same connection, if the relevant virtual server requires verification of a client certificate. While requesting hosts other than negotiated isn't something legal in HTTP/1.x, the HTTP/2 specification explicitly permits such requests for connection reuse and has introduced a special response code 421. According to RFC 7540 Section 9.1.2 this code can be sent by a server that is not configured to produce responses for the combination of scheme and authority that are included in the request URI. And the client may retry the request over a different connection. Now this code is used for requests that aren't authorized in current connection. After receiving the 421 response a client will be able to open a new connection, provide the required certificate and retry the request. Unfortunately, not all clients currently are able to handle it well. Notably Chrome just shows an error, while at least the latest version of Firefox retries the request over a new connection.
author Valentin Bartenev <vbart@nginx.com>
date Fri, 20 May 2016 18:41:17 +0300
parents dcfe355dfda4
children
line wrap: on
line source


/*
 * Copyright (C) Nginx, Inc.
 * Copyright (C) Valentin V. Bartenev
 * Copyright (C) 2015 Vlad Krasnov
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>


typedef struct {
    uint32_t  code;
    uint32_t  len;
} ngx_http_v2_huff_encode_code_t;


static ngx_http_v2_huff_encode_code_t  ngx_http_v2_huff_encode_table[256] =
{
    {0x00001ff8, 13}, {0x007fffd8, 23}, {0x0fffffe2, 28}, {0x0fffffe3, 28},
    {0x0fffffe4, 28}, {0x0fffffe5, 28}, {0x0fffffe6, 28}, {0x0fffffe7, 28},
    {0x0fffffe8, 28}, {0x00ffffea, 24}, {0x3ffffffc, 30}, {0x0fffffe9, 28},
    {0x0fffffea, 28}, {0x3ffffffd, 30}, {0x0fffffeb, 28}, {0x0fffffec, 28},
    {0x0fffffed, 28}, {0x0fffffee, 28}, {0x0fffffef, 28}, {0x0ffffff0, 28},
    {0x0ffffff1, 28}, {0x0ffffff2, 28}, {0x3ffffffe, 30}, {0x0ffffff3, 28},
    {0x0ffffff4, 28}, {0x0ffffff5, 28}, {0x0ffffff6, 28}, {0x0ffffff7, 28},
    {0x0ffffff8, 28}, {0x0ffffff9, 28}, {0x0ffffffa, 28}, {0x0ffffffb, 28},
    {0x00000014,  6}, {0x000003f8, 10}, {0x000003f9, 10}, {0x00000ffa, 12},
    {0x00001ff9, 13}, {0x00000015,  6}, {0x000000f8,  8}, {0x000007fa, 11},
    {0x000003fa, 10}, {0x000003fb, 10}, {0x000000f9,  8}, {0x000007fb, 11},
    {0x000000fa,  8}, {0x00000016,  6}, {0x00000017,  6}, {0x00000018,  6},
    {0x00000000,  5}, {0x00000001,  5}, {0x00000002,  5}, {0x00000019,  6},
    {0x0000001a,  6}, {0x0000001b,  6}, {0x0000001c,  6}, {0x0000001d,  6},
    {0x0000001e,  6}, {0x0000001f,  6}, {0x0000005c,  7}, {0x000000fb,  8},
    {0x00007ffc, 15}, {0x00000020,  6}, {0x00000ffb, 12}, {0x000003fc, 10},
    {0x00001ffa, 13}, {0x00000021,  6}, {0x0000005d,  7}, {0x0000005e,  7},
    {0x0000005f,  7}, {0x00000060,  7}, {0x00000061,  7}, {0x00000062,  7},
    {0x00000063,  7}, {0x00000064,  7}, {0x00000065,  7}, {0x00000066,  7},
    {0x00000067,  7}, {0x00000068,  7}, {0x00000069,  7}, {0x0000006a,  7},
    {0x0000006b,  7}, {0x0000006c,  7}, {0x0000006d,  7}, {0x0000006e,  7},
    {0x0000006f,  7}, {0x00000070,  7}, {0x00000071,  7}, {0x00000072,  7},
    {0x000000fc,  8}, {0x00000073,  7}, {0x000000fd,  8}, {0x00001ffb, 13},
    {0x0007fff0, 19}, {0x00001ffc, 13}, {0x00003ffc, 14}, {0x00000022,  6},
    {0x00007ffd, 15}, {0x00000003,  5}, {0x00000023,  6}, {0x00000004,  5},
    {0x00000024,  6}, {0x00000005,  5}, {0x00000025,  6}, {0x00000026,  6},
    {0x00000027,  6}, {0x00000006,  5}, {0x00000074,  7}, {0x00000075,  7},
    {0x00000028,  6}, {0x00000029,  6}, {0x0000002a,  6}, {0x00000007,  5},
    {0x0000002b,  6}, {0x00000076,  7}, {0x0000002c,  6}, {0x00000008,  5},
    {0x00000009,  5}, {0x0000002d,  6}, {0x00000077,  7}, {0x00000078,  7},
    {0x00000079,  7}, {0x0000007a,  7}, {0x0000007b,  7}, {0x00007ffe, 15},
    {0x000007fc, 11}, {0x00003ffd, 14}, {0x00001ffd, 13}, {0x0ffffffc, 28},
    {0x000fffe6, 20}, {0x003fffd2, 22}, {0x000fffe7, 20}, {0x000fffe8, 20},
    {0x003fffd3, 22}, {0x003fffd4, 22}, {0x003fffd5, 22}, {0x007fffd9, 23},
    {0x003fffd6, 22}, {0x007fffda, 23}, {0x007fffdb, 23}, {0x007fffdc, 23},
    {0x007fffdd, 23}, {0x007fffde, 23}, {0x00ffffeb, 24}, {0x007fffdf, 23},
    {0x00ffffec, 24}, {0x00ffffed, 24}, {0x003fffd7, 22}, {0x007fffe0, 23},
    {0x00ffffee, 24}, {0x007fffe1, 23}, {0x007fffe2, 23}, {0x007fffe3, 23},
    {0x007fffe4, 23}, {0x001fffdc, 21}, {0x003fffd8, 22}, {0x007fffe5, 23},
    {0x003fffd9, 22}, {0x007fffe6, 23}, {0x007fffe7, 23}, {0x00ffffef, 24},
    {0x003fffda, 22}, {0x001fffdd, 21}, {0x000fffe9, 20}, {0x003fffdb, 22},
    {0x003fffdc, 22}, {0x007fffe8, 23}, {0x007fffe9, 23}, {0x001fffde, 21},
    {0x007fffea, 23}, {0x003fffdd, 22}, {0x003fffde, 22}, {0x00fffff0, 24},
    {0x001fffdf, 21}, {0x003fffdf, 22}, {0x007fffeb, 23}, {0x007fffec, 23},
    {0x001fffe0, 21}, {0x001fffe1, 21}, {0x003fffe0, 22}, {0x001fffe2, 21},
    {0x007fffed, 23}, {0x003fffe1, 22}, {0x007fffee, 23}, {0x007fffef, 23},
    {0x000fffea, 20}, {0x003fffe2, 22}, {0x003fffe3, 22}, {0x003fffe4, 22},
    {0x007ffff0, 23}, {0x003fffe5, 22}, {0x003fffe6, 22}, {0x007ffff1, 23},
    {0x03ffffe0, 26}, {0x03ffffe1, 26}, {0x000fffeb, 20}, {0x0007fff1, 19},
    {0x003fffe7, 22}, {0x007ffff2, 23}, {0x003fffe8, 22}, {0x01ffffec, 25},
    {0x03ffffe2, 26}, {0x03ffffe3, 26}, {0x03ffffe4, 26}, {0x07ffffde, 27},
    {0x07ffffdf, 27}, {0x03ffffe5, 26}, {0x00fffff1, 24}, {0x01ffffed, 25},
    {0x0007fff2, 19}, {0x001fffe3, 21}, {0x03ffffe6, 26}, {0x07ffffe0, 27},
    {0x07ffffe1, 27}, {0x03ffffe7, 26}, {0x07ffffe2, 27}, {0x00fffff2, 24},
    {0x001fffe4, 21}, {0x001fffe5, 21}, {0x03ffffe8, 26}, {0x03ffffe9, 26},
    {0x0ffffffd, 28}, {0x07ffffe3, 27}, {0x07ffffe4, 27}, {0x07ffffe5, 27},
    {0x000fffec, 20}, {0x00fffff3, 24}, {0x000fffed, 20}, {0x001fffe6, 21},
    {0x003fffe9, 22}, {0x001fffe7, 21}, {0x001fffe8, 21}, {0x007ffff3, 23},
    {0x003fffea, 22}, {0x003fffeb, 22}, {0x01ffffee, 25}, {0x01ffffef, 25},
    {0x00fffff4, 24}, {0x00fffff5, 24}, {0x03ffffea, 26}, {0x007ffff4, 23},
    {0x03ffffeb, 26}, {0x07ffffe6, 27}, {0x03ffffec, 26}, {0x03ffffed, 26},
    {0x07ffffe7, 27}, {0x07ffffe8, 27}, {0x07ffffe9, 27}, {0x07ffffea, 27},
    {0x07ffffeb, 27}, {0x0ffffffe, 28}, {0x07ffffec, 27}, {0x07ffffed, 27},
    {0x07ffffee, 27}, {0x07ffffef, 27}, {0x07fffff0, 27}, {0x03ffffee, 26}
};


/* same as above, but embeds lowercase transformation */
static ngx_http_v2_huff_encode_code_t  ngx_http_v2_huff_encode_table_lc[256] =
{
    {0x00001ff8, 13}, {0x007fffd8, 23}, {0x0fffffe2, 28}, {0x0fffffe3, 28},
    {0x0fffffe4, 28}, {0x0fffffe5, 28}, {0x0fffffe6, 28}, {0x0fffffe7, 28},
    {0x0fffffe8, 28}, {0x00ffffea, 24}, {0x3ffffffc, 30}, {0x0fffffe9, 28},
    {0x0fffffea, 28}, {0x3ffffffd, 30}, {0x0fffffeb, 28}, {0x0fffffec, 28},
    {0x0fffffed, 28}, {0x0fffffee, 28}, {0x0fffffef, 28}, {0x0ffffff0, 28},
    {0x0ffffff1, 28}, {0x0ffffff2, 28}, {0x3ffffffe, 30}, {0x0ffffff3, 28},
    {0x0ffffff4, 28}, {0x0ffffff5, 28}, {0x0ffffff6, 28}, {0x0ffffff7, 28},
    {0x0ffffff8, 28}, {0x0ffffff9, 28}, {0x0ffffffa, 28}, {0x0ffffffb, 28},
    {0x00000014,  6}, {0x000003f8, 10}, {0x000003f9, 10}, {0x00000ffa, 12},
    {0x00001ff9, 13}, {0x00000015,  6}, {0x000000f8,  8}, {0x000007fa, 11},
    {0x000003fa, 10}, {0x000003fb, 10}, {0x000000f9,  8}, {0x000007fb, 11},
    {0x000000fa,  8}, {0x00000016,  6}, {0x00000017,  6}, {0x00000018,  6},
    {0x00000000,  5}, {0x00000001,  5}, {0x00000002,  5}, {0x00000019,  6},
    {0x0000001a,  6}, {0x0000001b,  6}, {0x0000001c,  6}, {0x0000001d,  6},
    {0x0000001e,  6}, {0x0000001f,  6}, {0x0000005c,  7}, {0x000000fb,  8},
    {0x00007ffc, 15}, {0x00000020,  6}, {0x00000ffb, 12}, {0x000003fc, 10},
    {0x00001ffa, 13}, {0x00000003,  5}, {0x00000023,  6}, {0x00000004,  5},
    {0x00000024,  6}, {0x00000005,  5}, {0x00000025,  6}, {0x00000026,  6},
    {0x00000027,  6}, {0x00000006,  5}, {0x00000074,  7}, {0x00000075,  7},
    {0x00000028,  6}, {0x00000029,  6}, {0x0000002a,  6}, {0x00000007,  5},
    {0x0000002b,  6}, {0x00000076,  7}, {0x0000002c,  6}, {0x00000008,  5},
    {0x00000009,  5}, {0x0000002d,  6}, {0x00000077,  7}, {0x00000078,  7},
    {0x00000079,  7}, {0x0000007a,  7}, {0x0000007b,  7}, {0x00001ffb, 13},
    {0x0007fff0, 19}, {0x00001ffc, 13}, {0x00003ffc, 14}, {0x00000022,  6},
    {0x00007ffd, 15}, {0x00000003,  5}, {0x00000023,  6}, {0x00000004,  5},
    {0x00000024,  6}, {0x00000005,  5}, {0x00000025,  6}, {0x00000026,  6},
    {0x00000027,  6}, {0x00000006,  5}, {0x00000074,  7}, {0x00000075,  7},
    {0x00000028,  6}, {0x00000029,  6}, {0x0000002a,  6}, {0x00000007,  5},
    {0x0000002b,  6}, {0x00000076,  7}, {0x0000002c,  6}, {0x00000008,  5},
    {0x00000009,  5}, {0x0000002d,  6}, {0x00000077,  7}, {0x00000078,  7},
    {0x00000079,  7}, {0x0000007a,  7}, {0x0000007b,  7}, {0x00007ffe, 15},
    {0x000007fc, 11}, {0x00003ffd, 14}, {0x00001ffd, 13}, {0x0ffffffc, 28},
    {0x000fffe6, 20}, {0x003fffd2, 22}, {0x000fffe7, 20}, {0x000fffe8, 20},
    {0x003fffd3, 22}, {0x003fffd4, 22}, {0x003fffd5, 22}, {0x007fffd9, 23},
    {0x003fffd6, 22}, {0x007fffda, 23}, {0x007fffdb, 23}, {0x007fffdc, 23},
    {0x007fffdd, 23}, {0x007fffde, 23}, {0x00ffffeb, 24}, {0x007fffdf, 23},
    {0x00ffffec, 24}, {0x00ffffed, 24}, {0x003fffd7, 22}, {0x007fffe0, 23},
    {0x00ffffee, 24}, {0x007fffe1, 23}, {0x007fffe2, 23}, {0x007fffe3, 23},
    {0x007fffe4, 23}, {0x001fffdc, 21}, {0x003fffd8, 22}, {0x007fffe5, 23},
    {0x003fffd9, 22}, {0x007fffe6, 23}, {0x007fffe7, 23}, {0x00ffffef, 24},
    {0x003fffda, 22}, {0x001fffdd, 21}, {0x000fffe9, 20}, {0x003fffdb, 22},
    {0x003fffdc, 22}, {0x007fffe8, 23}, {0x007fffe9, 23}, {0x001fffde, 21},
    {0x007fffea, 23}, {0x003fffdd, 22}, {0x003fffde, 22}, {0x00fffff0, 24},
    {0x001fffdf, 21}, {0x003fffdf, 22}, {0x007fffeb, 23}, {0x007fffec, 23},
    {0x001fffe0, 21}, {0x001fffe1, 21}, {0x003fffe0, 22}, {0x001fffe2, 21},
    {0x007fffed, 23}, {0x003fffe1, 22}, {0x007fffee, 23}, {0x007fffef, 23},
    {0x000fffea, 20}, {0x003fffe2, 22}, {0x003fffe3, 22}, {0x003fffe4, 22},
    {0x007ffff0, 23}, {0x003fffe5, 22}, {0x003fffe6, 22}, {0x007ffff1, 23},
    {0x03ffffe0, 26}, {0x03ffffe1, 26}, {0x000fffeb, 20}, {0x0007fff1, 19},
    {0x003fffe7, 22}, {0x007ffff2, 23}, {0x003fffe8, 22}, {0x01ffffec, 25},
    {0x03ffffe2, 26}, {0x03ffffe3, 26}, {0x03ffffe4, 26}, {0x07ffffde, 27},
    {0x07ffffdf, 27}, {0x03ffffe5, 26}, {0x00fffff1, 24}, {0x01ffffed, 25},
    {0x0007fff2, 19}, {0x001fffe3, 21}, {0x03ffffe6, 26}, {0x07ffffe0, 27},
    {0x07ffffe1, 27}, {0x03ffffe7, 26}, {0x07ffffe2, 27}, {0x00fffff2, 24},
    {0x001fffe4, 21}, {0x001fffe5, 21}, {0x03ffffe8, 26}, {0x03ffffe9, 26},
    {0x0ffffffd, 28}, {0x07ffffe3, 27}, {0x07ffffe4, 27}, {0x07ffffe5, 27},
    {0x000fffec, 20}, {0x00fffff3, 24}, {0x000fffed, 20}, {0x001fffe6, 21},
    {0x003fffe9, 22}, {0x001fffe7, 21}, {0x001fffe8, 21}, {0x007ffff3, 23},
    {0x003fffea, 22}, {0x003fffeb, 22}, {0x01ffffee, 25}, {0x01ffffef, 25},
    {0x00fffff4, 24}, {0x00fffff5, 24}, {0x03ffffea, 26}, {0x007ffff4, 23},
    {0x03ffffeb, 26}, {0x07ffffe6, 27}, {0x03ffffec, 26}, {0x03ffffed, 26},
    {0x07ffffe7, 27}, {0x07ffffe8, 27}, {0x07ffffe9, 27}, {0x07ffffea, 27},
    {0x07ffffeb, 27}, {0x0ffffffe, 28}, {0x07ffffec, 27}, {0x07ffffed, 27},
    {0x07ffffee, 27}, {0x07ffffef, 27}, {0x07fffff0, 27}, {0x03ffffee, 26}
};


#if (NGX_PTR_SIZE == 8)

#if (NGX_HAVE_LITTLE_ENDIAN)

#if (NGX_HAVE_GCC_BSWAP64)
#define ngx_http_v2_huff_encode_buf(dst, buf)                                 \
    (*(uint64_t *) (dst) = __builtin_bswap64(buf))
#else
#define ngx_http_v2_huff_encode_buf(dst, buf)                                 \
    ((dst)[0] = (u_char) ((buf) >> 56),                                       \
     (dst)[1] = (u_char) ((buf) >> 48),                                       \
     (dst)[2] = (u_char) ((buf) >> 40),                                       \
     (dst)[3] = (u_char) ((buf) >> 32),                                       \
     (dst)[4] = (u_char) ((buf) >> 24),                                       \
     (dst)[5] = (u_char) ((buf) >> 16),                                       \
     (dst)[6] = (u_char) ((buf) >> 8),                                        \
     (dst)[7] = (u_char)  (buf))
#endif

#else /* !NGX_HAVE_LITTLE_ENDIAN */
#define ngx_http_v2_huff_encode_buf(dst, buf)                                 \
    (*(uint64_t *) (dst) = (buf))
#endif

#else /* NGX_PTR_SIZE == 4 */

#define ngx_http_v2_huff_encode_buf(dst, buf)                                 \
    (*(uint32_t *) (dst) = htonl(buf))

#endif


size_t
ngx_http_v2_huff_encode(u_char *src, size_t len, u_char *dst, ngx_uint_t lower)
{
    u_char                          *end;
    size_t                           hlen;
    ngx_uint_t                       buf, pending, code;
    ngx_http_v2_huff_encode_code_t  *table, *next;

    table = lower ? ngx_http_v2_huff_encode_table_lc
                  : ngx_http_v2_huff_encode_table;
    hlen = 0;
    buf = 0;
    pending = 0;

    end = src + len;

    while (src != end) {
        next = &table[*src++];

        code = next->code;
        pending += next->len;

        /* accumulate bits */
        if (pending < sizeof(buf) * 8) {
            buf |= code << (sizeof(buf) * 8 - pending);
            continue;
        }

        if (hlen + sizeof(buf) >= len) {
            return 0;
        }

        pending -= sizeof(buf) * 8;

        buf |= code >> pending;

        ngx_http_v2_huff_encode_buf(&dst[hlen], buf);

        hlen += sizeof(buf);

        buf = pending ? code << (sizeof(buf) * 8 - pending) : 0;
    }

    if (pending == 0) {
        return hlen;
    }

    buf |= (ngx_uint_t) -1 >> pending;

    pending = ngx_align(pending, 8);

    if (hlen + pending / 8 >= len) {
        return 0;
    }

    buf >>= sizeof(buf) * 8 - pending;

    do {
        pending -= 8;
        dst[hlen++] = (u_char) (buf >> pending);
    } while (pending);

    return hlen;
}