# HG changeset patch # User Vlad Krasnov # Date 1498167669 25200 # Thu Jun 22 14:41:09 2017 -0700 # Node ID 895cea03ac21fb18d2c2ba32389cd67dc74ddbd0 # Parent a39bc74873faf9e5bea616561b43f6ecc55229f9 HTTP/2: add support for HPACK encoding Add support for full HPACK encoding as per RFC7541. This modification improves header compression ratio by 5-10% for the first response, and by 40-95% for consequential responses on the connection. The implementation is similar to the one used by Cloudflare. diff -r a39bc74873fa -r 895cea03ac21 auto/modules --- a/auto/modules Mon Jun 19 14:25:42 2017 +0300 +++ b/auto/modules Thu Jun 22 14:41:09 2017 -0700 @@ -436,6 +436,10 @@ . auto/module fi + if [ $HTTP_V2_HPACK_ENC = YES ]; then + have=NGX_HTTP_V2_HPACK_ENC . auto/have + fi + if :; then ngx_module_name=ngx_http_static_module ngx_module_incs= diff -r a39bc74873fa -r 895cea03ac21 auto/options --- a/auto/options Mon Jun 19 14:25:42 2017 +0300 +++ b/auto/options Thu Jun 22 14:41:09 2017 -0700 @@ -59,6 +59,7 @@ HTTP_GZIP=YES HTTP_SSL=NO HTTP_V2=NO +HTTP_V2_HPACK_ENC=NO HTTP_SSI=YES HTTP_POSTPONE=NO HTTP_REALIP=NO @@ -221,6 +222,7 @@ --with-http_ssl_module) HTTP_SSL=YES ;; --with-http_v2_module) HTTP_V2=YES ;; + --with-http_v2_hpack_enc) HTTP_V2_HPACK_ENC=YES ;; --with-http_realip_module) HTTP_REALIP=YES ;; --with-http_addition_module) HTTP_ADDITION=YES ;; --with-http_xslt_module) HTTP_XSLT=YES ;; @@ -430,6 +432,7 @@ --with-http_ssl_module enable ngx_http_ssl_module --with-http_v2_module enable ngx_http_v2_module + --with-http_v2_hpack_enc enable ngx_http_v2_hpack_enc --with-http_realip_module enable ngx_http_realip_module --with-http_addition_module enable ngx_http_addition_module --with-http_xslt_module enable ngx_http_xslt_module diff -r a39bc74873fa -r 895cea03ac21 src/core/ngx_murmurhash.c --- a/src/core/ngx_murmurhash.c Mon Jun 19 14:25:42 2017 +0300 +++ b/src/core/ngx_murmurhash.c Thu Jun 22 14:41:09 2017 -0700 @@ -50,3 +50,63 @@ return h; } + + +uint64_t +ngx_murmur_hash2_64(u_char *data, size_t len, uint64_t seed) +{ + uint64_t h, k; + + h = seed ^ len; + + while (len >= 8) { + k = data[0]; + k |= data[1] << 8; + k |= data[2] << 16; + k |= data[3] << 24; + k |= (uint64_t)data[4] << 32; + k |= (uint64_t)data[5] << 40; + k |= (uint64_t)data[6] << 48; + k |= (uint64_t)data[7] << 56; + + k *= 0xc6a4a7935bd1e995ull; + k ^= k >> 47; + k *= 0xc6a4a7935bd1e995ull; + + h ^= k; + h *= 0xc6a4a7935bd1e995ull; + + data += 8; + len -= 8; + } + + switch (len) { + case 7: + h ^= (uint64_t)data[6] << 48; + /* fall through */ + case 6: + h ^= (uint64_t)data[5] << 40; + /* fall through */ + case 5: + h ^= (uint64_t)data[4] << 32; + /* fall through */ + case 4: + h ^= data[3] << 24; + /* fall through */ + case 3: + h ^= data[2] << 16; + /* fall through */ + case 2: + h ^= data[1] << 8; + /* fall through */ + case 1: + h ^= data[0]; + h *= 0xc6a4a7935bd1e995ull; + } + + h ^= h >> 47; + h *= 0xc6a4a7935bd1e995ull; + h ^= h >> 47; + + return h; +} diff -r a39bc74873fa -r 895cea03ac21 src/core/ngx_murmurhash.h --- a/src/core/ngx_murmurhash.h Mon Jun 19 14:25:42 2017 +0300 +++ b/src/core/ngx_murmurhash.h Thu Jun 22 14:41:09 2017 -0700 @@ -15,5 +15,7 @@ uint32_t ngx_murmur_hash2(u_char *data, size_t len); +uint64_t ngx_murmur_hash2_64(u_char *data, size_t len, uint64_t seed); + #endif /* _NGX_MURMURHASH_H_INCLUDED_ */ diff -r a39bc74873fa -r 895cea03ac21 src/http/v2/ngx_http_v2.c --- a/src/http/v2/ngx_http_v2.c Mon Jun 19 14:25:42 2017 +0300 +++ b/src/http/v2/ngx_http_v2.c Thu Jun 22 14:41:09 2017 -0700 @@ -245,6 +245,8 @@ h2c->frame_size = NGX_HTTP_V2_DEFAULT_FRAME_SIZE; + h2c->max_hpack_table_size = NGX_HTTP_V2_DEFAULT_HPACK_TABLE_SIZE; + h2scf = ngx_http_get_module_srv_conf(hc->conf_ctx, ngx_http_v2_module); h2c->pool = ngx_create_pool(h2scf->pool_size, h2c->connection->log); @@ -2018,6 +2020,17 @@ h2c->frame_size = value; break; + case NGX_HTTP_V2_HEADER_TABLE_SIZE_SETTING: + + if (value > NGX_HTTP_V2_MAX_HPACK_TABLE_SIZE) { + h2c->max_hpack_table_size = NGX_HTTP_V2_MAX_HPACK_TABLE_SIZE; + } else { + h2c->max_hpack_table_size = value; + } + + h2c->indicate_resize = 1; + break; + default: break; } diff -r a39bc74873fa -r 895cea03ac21 src/http/v2/ngx_http_v2.h --- a/src/http/v2/ngx_http_v2.h Mon Jun 19 14:25:42 2017 +0300 +++ b/src/http/v2/ngx_http_v2.h Thu Jun 22 14:41:09 2017 -0700 @@ -49,6 +49,13 @@ #define NGX_HTTP_V2_MAX_WINDOW ((1U << 31) - 1) #define NGX_HTTP_V2_DEFAULT_WINDOW 65535 +#define HPACK_ENC_HTABLE_SZ 128 /* better to keep a PoT < 64k */ +#define HPACK_ENC_HTABLE_ENTRIES ((HPACK_ENC_HTABLE_SZ * 100) / 128) +#define HPACK_ENC_DYNAMIC_KEY_TBL_SZ 10 /* 10 is sufficient for most */ +#define HPACK_ENC_MAX_ENTRY 512 /* longest header size to match */ + +#define NGX_HTTP_V2_DEFAULT_HPACK_TABLE_SIZE 4096 +#define NGX_HTTP_V2_MAX_HPACK_TABLE_SIZE 16384 /* < 64k */ typedef struct ngx_http_v2_connection_s ngx_http_v2_connection_t; typedef struct ngx_http_v2_node_s ngx_http_v2_node_t; @@ -110,6 +117,46 @@ } ngx_http_v2_hpack_t; +#if (NGX_HTTP_V2_HPACK_ENC) +typedef struct { + uint64_t hash_val; + uint32_t index; + uint16_t pos; + uint16_t klen, vlen; + uint16_t size; + uint16_t next; +} ngx_http_v2_hpack_enc_entry_t; + + +typedef struct { + uint64_t hash_val; + uint32_t index; + uint16_t pos; + uint16_t klen; +} ngx_http_v2_hpack_name_entry_t; + + +typedef struct { + size_t size; /* size as defined in RFC 7541 */ + uint32_t top; /* the last entry */ + uint32_t pos; + uint16_t n_elems; /* number of elements */ + uint16_t base; /* index of the oldest entry */ + uint16_t last; /* index of the newest entry */ + + /* hash table for dynamic entries, instead using a generic hash table, + which would be too slow to process a significant amount of headers, + this table is not determenistic, and might ocasionally fail to insert + a value, at the cost of slightly worse compression, but significantly + faster performance */ + ngx_http_v2_hpack_enc_entry_t htable[HPACK_ENC_HTABLE_SZ]; + ngx_http_v2_hpack_name_entry_t heads[HPACK_ENC_DYNAMIC_KEY_TBL_SZ]; + u_char storage[NGX_HTTP_V2_MAX_HPACK_TABLE_SIZE + + HPACK_ENC_MAX_ENTRY]; +} ngx_http_v2_hpack_enc_t; +#endif + + struct ngx_http_v2_connection_s { ngx_connection_t *connection; ngx_http_connection_t *http_connection; @@ -122,6 +169,8 @@ size_t frame_size; + size_t max_hpack_table_size; + ngx_queue_t waiting; ngx_http_v2_state_t state; @@ -146,6 +195,11 @@ unsigned settings_ack:1; unsigned blocked:1; unsigned goaway:1; + unsigned indicate_resize:1; + +#if (NGX_HTTP_V2_HPACK_ENC) + ngx_http_v2_hpack_enc_t hpack_enc; +#endif }; @@ -347,4 +401,31 @@ #define ngx_http_v2_write_sid ngx_http_v2_write_uint32 +u_char *ngx_http_v2_string_encode(u_char *dst, u_char *src, size_t len, + u_char *tmp, ngx_uint_t lower); + +u_char * +ngx_http_v2_write_int(u_char *pos, ngx_uint_t prefix, ngx_uint_t value); + +#define ngx_http_v2_write_name(dst, src, len, tmp) \ + ngx_http_v2_string_encode(dst, src, len, tmp, 1) +#define ngx_http_v2_write_value(dst, src, len, tmp) \ + ngx_http_v2_string_encode(dst, src, len, tmp, 0) + +u_char * +ngx_http_v2_write_header(ngx_http_v2_connection_t *h2c, u_char *pos, + u_char *key, size_t key_len, u_char *value, size_t value_len, + u_char *tmp); + +void +ngx_http_v2_table_resize(ngx_http_v2_connection_t *h2c); + +#define ngx_http_v2_write_header_str(key, value) \ + ngx_http_v2_write_header(h2c, pos, (u_char *) key, sizeof(key) - 1, \ + (u_char *) value, sizeof(value) - 1, tmp); + +#define ngx_http_v2_write_header_tbl(key, val) \ + ngx_http_v2_write_header(h2c, pos, (u_char *) key, sizeof(key) - 1, \ + val.data, val.len, tmp); + #endif /* _NGX_HTTP_V2_H_INCLUDED_ */ diff -r a39bc74873fa -r 895cea03ac21 src/http/v2/ngx_http_v2_filter_module.c --- a/src/http/v2/ngx_http_v2_filter_module.c Mon Jun 19 14:25:42 2017 +0300 +++ b/src/http/v2/ngx_http_v2_filter_module.c Thu Jun 22 14:41:09 2017 -0700 @@ -25,11 +25,6 @@ #define ngx_http_v2_indexed(i) (128 + (i)) #define ngx_http_v2_inc_indexed(i) (64 + (i)) -#define ngx_http_v2_write_name(dst, src, len, tmp) \ - ngx_http_v2_string_encode(dst, src, len, tmp, 1) -#define ngx_http_v2_write_value(dst, src, len, tmp) \ - ngx_http_v2_string_encode(dst, src, len, tmp, 0) - #define NGX_HTTP_V2_ENCODE_RAW 0 #define NGX_HTTP_V2_ENCODE_HUFF 0x80 @@ -53,10 +48,6 @@ #define NGX_HTTP_V2_NO_TRAILERS (ngx_http_v2_out_frame_t *) -1 -static u_char *ngx_http_v2_string_encode(u_char *dst, u_char *src, size_t len, - u_char *tmp, ngx_uint_t lower); -static u_char *ngx_http_v2_write_int(u_char *pos, ngx_uint_t prefix, - ngx_uint_t value); static ngx_http_v2_out_frame_t *ngx_http_v2_create_headers_frame( ngx_http_request_t *r, u_char *pos, u_char *end, ngx_uint_t fin); static ngx_http_v2_out_frame_t *ngx_http_v2_create_trailers_frame( @@ -142,6 +133,7 @@ ngx_http_core_loc_conf_t *clcf; ngx_http_core_srv_conf_t *cscf; u_char addr[NGX_SOCKADDR_STRLEN]; + ngx_http_v2_connection_t *h2c; static const u_char nginx[5] = "\x84\xaa\x63\x55\xe7"; #if (NGX_HTTP_GZIP) @@ -150,11 +142,9 @@ #endif static size_t nginx_ver_len = ngx_http_v2_literal_size(NGINX_VER); - static u_char nginx_ver[ngx_http_v2_literal_size(NGINX_VER)]; static size_t nginx_ver_build_len = ngx_http_v2_literal_size(NGINX_VER_BUILD); - static u_char nginx_ver_build[ngx_http_v2_literal_size(NGINX_VER_BUILD)]; if (!r->stream) { return ngx_http_next_header_filter(r); @@ -415,7 +405,7 @@ } tmp = ngx_palloc(r->pool, tmp_len); - pos = ngx_pnalloc(r->pool, len); + pos = ngx_pnalloc(r->pool, len + 15 + 1); if (pos == NULL || tmp == NULL) { return NGX_ERROR; @@ -423,6 +413,18 @@ start = pos; + h2c = r->stream->connection; + + if (h2c->indicate_resize) { + *pos = 32; + pos = ngx_http_v2_write_int(pos, ngx_http_v2_prefix(5), + h2c->max_hpack_table_size); + h2c->indicate_resize = 0; +#if (NGX_HTTP_V2_HPACK_ENC) + ngx_http_v2_table_resize(h2c); +#endif + } + ngx_log_debug1(NGX_LOG_DEBUG_HTTP, fc->log, 0, "http2 output header: \":status: %03ui\"", r->headers_out.status); @@ -431,67 +433,28 @@ *pos++ = status; } else { - *pos++ = ngx_http_v2_inc_indexed(NGX_HTTP_V2_STATUS_INDEX); - *pos++ = NGX_HTTP_V2_ENCODE_RAW | 3; - pos = ngx_sprintf(pos, "%03ui", r->headers_out.status); + ngx_sprintf(pos + 8, "%O3ui", r->headers_out.status); + pos = ngx_http_v2_write_header(h2c, pos, (u_char *)":status", + sizeof(":status") - 1, pos + 8, 3, tmp); } if (r->headers_out.server == NULL) { - if (clcf->server_tokens == NGX_HTTP_SERVER_TOKENS_ON) { - ngx_log_debug1(NGX_LOG_DEBUG_HTTP, fc->log, 0, - "http2 output header: \"server: %s\"", - NGINX_VER); + pos = ngx_http_v2_write_header_str("server", NGINX_VER); } else if (clcf->server_tokens == NGX_HTTP_SERVER_TOKENS_BUILD) { - ngx_log_debug1(NGX_LOG_DEBUG_HTTP, fc->log, 0, - "http2 output header: \"server: %s\"", - NGINX_VER_BUILD); + pos = ngx_http_v2_write_header_str("server", NGINX_VER_BUILD); } else { - ngx_log_debug0(NGX_LOG_DEBUG_HTTP, fc->log, 0, - "http2 output header: \"server: nginx\""); - } - - *pos++ = ngx_http_v2_inc_indexed(NGX_HTTP_V2_SERVER_INDEX); - - if (clcf->server_tokens == NGX_HTTP_SERVER_TOKENS_ON) { - if (nginx_ver[0] == '\0') { - p = ngx_http_v2_write_value(nginx_ver, (u_char *) NGINX_VER, - sizeof(NGINX_VER) - 1, tmp); - nginx_ver_len = p - nginx_ver; - } - - pos = ngx_cpymem(pos, nginx_ver, nginx_ver_len); - - } else if (clcf->server_tokens == NGX_HTTP_SERVER_TOKENS_BUILD) { - if (nginx_ver_build[0] == '\0') { - p = ngx_http_v2_write_value(nginx_ver_build, - (u_char *) NGINX_VER_BUILD, - sizeof(NGINX_VER_BUILD) - 1, tmp); - nginx_ver_build_len = p - nginx_ver_build; - } - - pos = ngx_cpymem(pos, nginx_ver_build, nginx_ver_build_len); - - } else { - pos = ngx_cpymem(pos, nginx, sizeof(nginx)); + pos = ngx_http_v2_write_header_str("server", "nginx"); } } if (r->headers_out.date == NULL) { - ngx_log_debug1(NGX_LOG_DEBUG_HTTP, fc->log, 0, - "http2 output header: \"date: %V\"", - &ngx_cached_http_time); - - *pos++ = ngx_http_v2_inc_indexed(NGX_HTTP_V2_DATE_INDEX); - pos = ngx_http_v2_write_value(pos, ngx_cached_http_time.data, - ngx_cached_http_time.len, tmp); + pos = ngx_http_v2_write_header_tbl("date", ngx_cached_http_time); } if (r->headers_out.content_type.len) { - *pos++ = ngx_http_v2_inc_indexed(NGX_HTTP_V2_CONTENT_TYPE_INDEX); - if (r->headers_out.content_type_len == r->headers_out.content_type.len && r->headers_out.charset.len) { @@ -517,64 +480,36 @@ r->headers_out.content_type.data = p - len; } - ngx_log_debug1(NGX_LOG_DEBUG_HTTP, fc->log, 0, - "http2 output header: \"content-type: %V\"", - &r->headers_out.content_type); - - pos = ngx_http_v2_write_value(pos, r->headers_out.content_type.data, - r->headers_out.content_type.len, tmp); + pos = ngx_http_v2_write_header_tbl("content-type", + r->headers_out.content_type); } if (r->headers_out.content_length == NULL && r->headers_out.content_length_n >= 0) { - ngx_log_debug1(NGX_LOG_DEBUG_HTTP, fc->log, 0, - "http2 output header: \"content-length: %O\"", - r->headers_out.content_length_n); - - *pos++ = ngx_http_v2_inc_indexed(NGX_HTTP_V2_CONTENT_LENGTH_INDEX); - - p = pos; - pos = ngx_sprintf(pos + 1, "%O", r->headers_out.content_length_n); - *p = NGX_HTTP_V2_ENCODE_RAW | (u_char) (pos - p - 1); + p = ngx_sprintf(pos + 15, "%O", r->headers_out.content_length_n); + pos = ngx_http_v2_write_header(h2c, pos, (u_char *)"content-length", + sizeof("content-length") - 1, pos + 15, + p - (pos + 15), tmp); } if (r->headers_out.last_modified == NULL && r->headers_out.last_modified_time != -1) { - *pos++ = ngx_http_v2_inc_indexed(NGX_HTTP_V2_LAST_MODIFIED_INDEX); - - ngx_http_time(pos, r->headers_out.last_modified_time); + ngx_http_time(pos + 14, r->headers_out.last_modified_time); len = sizeof("Wed, 31 Dec 1986 18:00:00 GMT") - 1; - - ngx_log_debug2(NGX_LOG_DEBUG_HTTP, fc->log, 0, - "http2 output header: \"last-modified: %*s\"", - len, pos); - - /* - * Date will always be encoded using huffman in the temporary buffer, - * so it's safe here to use src and dst pointing to the same address. - */ - pos = ngx_http_v2_write_value(pos, pos, len, tmp); + pos = ngx_http_v2_write_header(h2c, pos, (u_char *)"last-modified", + sizeof("last-modified") - 1, pos + 14, + len, tmp); } if (r->headers_out.location && r->headers_out.location->value.len) { - ngx_log_debug1(NGX_LOG_DEBUG_HTTP, fc->log, 0, - "http2 output header: \"location: %V\"", - &r->headers_out.location->value); - - *pos++ = ngx_http_v2_inc_indexed(NGX_HTTP_V2_LOCATION_INDEX); - pos = ngx_http_v2_write_value(pos, r->headers_out.location->value.data, - r->headers_out.location->value.len, tmp); + pos = ngx_http_v2_write_header_tbl("location", r->headers_out.location->value); } #if (NGX_HTTP_GZIP) if (r->gzip_vary) { - ngx_log_debug0(NGX_LOG_DEBUG_HTTP, fc->log, 0, - "http2 output header: \"vary: Accept-Encoding\""); - - *pos++ = ngx_http_v2_inc_indexed(NGX_HTTP_V2_VARY_INDEX); - pos = ngx_cpymem(pos, accept_encoding, sizeof(accept_encoding)); + pos = ngx_http_v2_write_header_str("vary", "Accept-Encoding"); } #endif @@ -597,23 +532,9 @@ continue; } -#if (NGX_DEBUG) - if (fc->log->log_level & NGX_LOG_DEBUG_HTTP) { - ngx_strlow(tmp, header[i].key.data, header[i].key.len); - - ngx_log_debug3(NGX_LOG_DEBUG_HTTP, fc->log, 0, - "http2 output header: \"%*s: %V\"", - header[i].key.len, tmp, &header[i].value); - } -#endif - - *pos++ = 0; - - pos = ngx_http_v2_write_name(pos, header[i].key.data, - header[i].key.len, tmp); - - pos = ngx_http_v2_write_value(pos, header[i].value.data, - header[i].value.len, tmp); + pos = ngx_http_v2_write_header(h2c, pos, header[i].key.data, + header[i].key.len, header[i].value.data, + header[i].value.len, tmp); } frame = ngx_http_v2_create_headers_frame(r, start, pos, r->header_only); @@ -643,11 +564,12 @@ static ngx_http_v2_out_frame_t * ngx_http_v2_create_trailers_frame(ngx_http_request_t *r) { - u_char *pos, *start, *tmp; - size_t len, tmp_len; - ngx_uint_t i; - ngx_list_part_t *part; - ngx_table_elt_t *header; + u_char *pos, *start, *tmp; + size_t len, tmp_len; + ngx_uint_t i; + ngx_list_part_t *part; + ngx_table_elt_t *header; + ngx_http_v2_connection_t *h2c; len = 0; tmp_len = 0; @@ -713,6 +635,8 @@ part = &r->headers_out.trailers.part; header = part->elts; + h2c = r->stream->connection; + for (i = 0; /* void */; i++) { if (i >= part->nelts) { @@ -739,20 +663,16 @@ } #endif - *pos++ = 0; - - pos = ngx_http_v2_write_name(pos, header[i].key.data, - header[i].key.len, tmp); - - pos = ngx_http_v2_write_value(pos, header[i].value.data, - header[i].value.len, tmp); + pos = ngx_http_v2_write_header(h2c, pos, header[i].key.data, + header[i].key.len, header[i].value.data, + header[i].value.len, tmp); } return ngx_http_v2_create_headers_frame(r, start, pos, 1); } -static u_char * +u_char * ngx_http_v2_string_encode(u_char *dst, u_char *src, size_t len, u_char *tmp, ngx_uint_t lower) { @@ -778,7 +698,7 @@ } -static u_char * +u_char * ngx_http_v2_write_int(u_char *pos, ngx_uint_t prefix, ngx_uint_t value) { if (value < prefix) { diff -r a39bc74873fa -r 895cea03ac21 src/http/v2/ngx_http_v2_table.c --- a/src/http/v2/ngx_http_v2_table.c Mon Jun 19 14:25:42 2017 +0300 +++ b/src/http/v2/ngx_http_v2_table.c Thu Jun 22 14:41:09 2017 -0700 @@ -347,3 +347,434 @@ return NGX_OK; } + + +#if (NGX_HTTP_V2_HPACK_ENC) + +static ngx_int_t +hpack_get_static_index(ngx_http_v2_connection_t *h2c, u_char *val, size_t len); + +static ngx_int_t +hpack_get_dynamic_index(ngx_http_v2_connection_t *h2c, uint64_t key_hash, + uint8_t *key, size_t key_len); + + +void +ngx_http_v2_table_resize(ngx_http_v2_connection_t *h2c) +{ + ngx_http_v2_hpack_enc_entry_t *table; + uint64_t idx; + + table = h2c->hpack_enc.htable; + + while (h2c->hpack_enc.size > h2c->max_hpack_table_size) { + idx = h2c->hpack_enc.base; + h2c->hpack_enc.base = table[idx].next; + h2c->hpack_enc.size -= table[idx].size; + table[idx].hash_val = 0; + h2c->hpack_enc.n_elems--; + } +} + + +/* checks if a header is in the hpack table - if so returns the table entry, + otherwise encodes and inserts into the table and returns 0, + if failed to insert into table, returns -1 */ +static ngx_int_t +ngx_http_v2_table_encode_strings(ngx_http_v2_connection_t *h2c, + size_t key_len, size_t val_len, uint8_t *key, uint8_t *val, + ngx_int_t *header_idx) +{ + uint64_t hash_val, key_hash, idx, lru; + int i; + size_t size = key_len + val_len + 32; + uint8_t *storage = h2c->hpack_enc.storage; + + ngx_http_v2_hpack_enc_entry_t *table; + ngx_http_v2_hpack_name_entry_t *name; + + *header_idx = NGX_ERROR; + /* step 1: compute the hash value of header */ + if (size > HPACK_ENC_MAX_ENTRY || size > h2c->max_hpack_table_size) { + return NGX_ERROR; + } + + key_hash = ngx_murmur_hash2_64(key, key_len, 0x01234); + hash_val = ngx_murmur_hash2_64(val, val_len, key_hash); + + if (hash_val == 0) { + return NGX_ERROR; + } + + /* step 2: check if full header in the table */ + idx = hash_val; + i = -1; + while (idx) { + /* at most 8 locations are checked, but most will be done in 1 or 2 */ + table = &h2c->hpack_enc.htable[idx % HPACK_ENC_HTABLE_SZ]; + if (table->hash_val == hash_val + && table->klen == key_len + && table->vlen == val_len + && ngx_memcmp(key, storage + table->pos, key_len) == 0 + && ngx_memcmp(val, storage + table->pos + key_len, val_len) == 0) + { + return (h2c->hpack_enc.top - table->index) + 61; + } + + if (table->hash_val == 0 && i == -1) { + i = idx % HPACK_ENC_HTABLE_SZ; + break; + } + + idx >>= 8; + } + + /* step 3: check if key is in one of the tables */ + *header_idx = hpack_get_static_index(h2c, key, key_len); + + if (i == -1) { + return NGX_ERROR; + } + + if (*header_idx == NGX_ERROR) { + *header_idx = hpack_get_dynamic_index(h2c, key_hash, key, key_len); + } + + /* step 4: store the new entry */ + table = h2c->hpack_enc.htable; + + if (h2c->hpack_enc.top == 0xffffffff) { + /* just to be on the safe side, avoid overflow */ + ngx_memset(&h2c->hpack_enc, 0, sizeof(ngx_http_v2_hpack_enc_t)); + } + + while ((h2c->hpack_enc.size + size > h2c->max_hpack_table_size) + || h2c->hpack_enc.n_elems == HPACK_ENC_HTABLE_ENTRIES) { + /* make space for the new entry first */ + idx = h2c->hpack_enc.base; + h2c->hpack_enc.base = table[idx].next; + h2c->hpack_enc.size -= table[idx].size; + table[idx].hash_val = 0; + h2c->hpack_enc.n_elems--; + } + + table[i] = (ngx_http_v2_hpack_enc_entry_t){.hash_val = hash_val, + .index = h2c->hpack_enc.top, + .pos = h2c->hpack_enc.pos, + .klen = key_len, + .vlen = val_len, + .size = size, + .next = 0}; + + table[h2c->hpack_enc.last].next = i; + if (h2c->hpack_enc.n_elems == 0) { + h2c->hpack_enc.base = i; + } + + h2c->hpack_enc.last = i; + h2c->hpack_enc.top++; + h2c->hpack_enc.size += size; + h2c->hpack_enc.n_elems++; + + /* update header name lookup */ + if (*header_idx == NGX_ERROR ) { + lru = h2c->hpack_enc.top; + + for (i=0; ihpack_enc.heads[i]; + + if ( name->hash_val == 0 || (name->hash_val == key_hash + && ngx_memcmp(storage + name->pos, key, key_len) == 0) ) + { + name->hash_val = key_hash; + name->pos = h2c->hpack_enc.pos; + name->index = h2c->hpack_enc.top - 1; + break; + } + + if (lru > name->index) { + lru = name->index; + idx = i; + } + } + + if (i == HPACK_ENC_DYNAMIC_KEY_TBL_SZ) { + name = &h2c->hpack_enc.heads[idx]; + name->hash_val = hash_val; + name->pos = h2c->hpack_enc.pos; + name->index = h2c->hpack_enc.top - 1; + } + } + + ngx_memcpy(storage + h2c->hpack_enc.pos, key, key_len); + ngx_memcpy(storage + h2c->hpack_enc.pos + key_len, val, val_len); + + h2c->hpack_enc.pos += size; + if (h2c->hpack_enc.pos > NGX_HTTP_V2_MAX_HPACK_TABLE_SIZE) { + h2c->hpack_enc.pos = 0; + } + + return NGX_OK; +} + + +u_char * +ngx_http_v2_write_header(ngx_http_v2_connection_t *h2c, u_char *pos, + u_char *key, size_t key_len, + u_char *value, size_t value_len, + u_char *tmp) +{ + ngx_int_t idx, header_idx; + + ngx_log_debug4(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, + "http2 output header: %*s: %*s", key_len, key, value_len, + value); + + /* attempt to find the value in the dynamic table */ + idx = ngx_http_v2_table_encode_strings(h2c, key_len, value_len, key, value, + &header_idx); + + if (idx > 0) { + /* positive index indicates success */ + ngx_log_debug1(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, + "http2 hpack encode: Indexed Header Field: %ud", idx); + + *pos = 128; + pos = ngx_http_v2_write_int(pos, ngx_http_v2_prefix(7), idx); + + } else { + + if (header_idx == NGX_ERROR) { /* if key is not present */ + + if (idx == NGX_ERROR) { /* if header was not added */ + *pos++ = 0; + + ngx_log_debug0(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, + "http2 hpack encode: Literal Header Field without" + " Indexing — New Name"); + } else { /* if header was added */ + *pos++ = 64; + + ngx_log_debug0(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, + "http2 hpack encode: Literal Header Field with " + "Incremental Indexing — New Name"); + } + + pos = ngx_http_v2_write_name(pos, key, key_len, tmp); + + } else { /* if key is present */ + + if (idx == NGX_ERROR) { + *pos = 0; + pos = ngx_http_v2_write_int(pos, ngx_http_v2_prefix(4), header_idx); + + ngx_log_debug1(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, + "http2 hpack encode: Literal Header Field without" + " Indexing — Indexed Name: %ud", header_idx); + } else { + *pos = 64; + pos = ngx_http_v2_write_int(pos, ngx_http_v2_prefix(6), header_idx); + + ngx_log_debug1(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, + "http2 hpack encode: Literal Header Field with " + "Incremental Indexing — Indexed Name: %ud", header_idx); + } + } + + pos = ngx_http_v2_write_value(pos, value, value_len, tmp); + } + + return pos; +} + + +static ngx_int_t +hpack_get_dynamic_index(ngx_http_v2_connection_t *h2c, uint64_t key_hash, + uint8_t *key, size_t key_len) +{ + ngx_http_v2_hpack_name_entry_t *name; + int i; + + for (i=0; ihpack_enc.heads[i]; + + if (name->hash_val == key_hash + && ngx_memcmp(h2c->hpack_enc.storage + name->pos, key, key_len) == 0) + { + if (name->index >= h2c->hpack_enc.top - h2c->hpack_enc.n_elems) { + return (h2c->hpack_enc.top - name->index) + 61; + } + break; + } + } + + return NGX_ERROR; +} + + +/* decide if a given header is present in the static dictionary, this could be + done in several ways, but it seems the fastest one is "exhaustive" search */ +static ngx_int_t +hpack_get_static_index(ngx_http_v2_connection_t *h2c, u_char *val, size_t len) +{ + /* the static dictionary of response only headers, + although response headers can be put by origin, + that would be rare */ + static const struct { + u_char len; + const u_char val[28]; + u_char idx; + } server_headers[] = { + { 3, "age", 21},//0 + { 3, "via", 60}, + { 4, "date", 33},//2 + { 4, "etag", 34}, + { 4, "link", 45}, + { 4, "vary", 59}, + { 5, "allow", 22},//6 + { 6, "server", 54},//7 + { 7, "expires", 36},//8 + { 7, "refresh", 52}, + { 8, "location", 46},//10 + {10, "set-cookie", 55},//11 + {11, "retry-after", 53},//12 + {12, "content-type", 31},//13 + {13, "content-range", 30},//14 + {13, "accept-ranges", 18}, + {13, "cache-control", 24}, + {13, "last-modified", 44}, + {14, "content-length", 28},//18 + {16, "content-encoding", 26},//19 + {16, "content-language", 27}, + {16, "content-location", 29}, + {16, "www-authenticate", 61}, + {17, "transfer-encoding", 57},//23 + {18, "proxy-authenticate", 48},//24 + {19, "content-disposition", 25},//25 + {25, "strict-transport-security", 56},//26 + {27, "access-control-allow-origin", 20},//27 + {99, "", 99}, + }, *header; + + /* for a given length, where to start the search + since minimal length is 3, the table has a -3 + offset */ + static const int8_t start_at[] = { + [3-3] = 0, + [4-3] = 2, + [5-3] = 6, + [6-3] = 7, + [7-3] = 8, + [8-3] = 10, + [9-3] = -1, + [10-3] = 11, + [11-3] = 12, + [12-3] = 13, + [13-3] = 14, + [14-3] = 18, + [15-3] = -1, + [16-3] = 19, + [17-3] = 23, + [18-3] = 24, + [19-3] = 25, + [20-3] = -1, + [21-3] = -1, + [22-3] = -1, + [23-3] = -1, + [24-3] = -1, + [25-3] = 26, + [26-3] = -1, + [27-3] = 27, + }; + + uint64_t pref; + size_t save_len = len, i; + int8_t start; + + /* early exit for out of bounds lengths */ + if (len < 3 || len > 27) { + return NGX_ERROR; + } + + start = start_at[len - 3]; + if (start == -1) { + /* exit for non existent lengths */ + return NGX_ERROR; + } + + header = &server_headers[start_at[len - 3]]; + + /* load first 8 bytes of key, for fast comparison */ + if (len < 8) { + pref = 0; + if (len >= 4) { + pref = *(uint32_t *)(val + len - 4) | 0x20202020; + len -= 4; + } + while (len > 0) { /* 3 iterations at most */ + pref = (pref << 8) ^ (val[len - 1] | 0x20); + len--; + } + } else { + pref = *(uint64_t *)val | 0x2020202020202020; + len -= 8; + } + + /* iterate over headers with the right length */ + while (header->len == save_len) { + /* quickly compare the first 8 bytes, most tests will end here */ + if (pref != *(uint64_t *) header->val) { + header++; + continue; + } + + if (len == 0) { + /* len == 0, indicates prefix held the entire key */ + return header->idx; + } + /* for longer keys compare the rest */ + i = 1 + (save_len + 7) % 8; /* align so we can compare in quadwords */ + + while (i + 8 <= save_len) { /* 3 iterations at most */ + if ( *(uint64_t *)&header->val[i] + != (*(uint64_t *) &val[i]| 0x2020202020202020) ) + { + header++; + i = 0; + break; + } + i += 8; + } + + if (i == 0) { + continue; + } + + /* found the corresponding entry in the static dictionary */ + return header->idx; + } + + return NGX_ERROR; +} + +#else + +u_char * +ngx_http_v2_write_header(ngx_http_v2_connection_t *h2c, u_char *pos, + u_char *key, size_t key_len, + u_char *value, size_t value_len, + u_char *tmp) +{ + ngx_log_debug4(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, + "http2 output header: %*s: %*s", key_len, key, value_len, + value); + + *pos++ = 64; + pos = ngx_http_v2_write_name(pos, key, key_len, tmp); + pos = ngx_http_v2_write_value(pos, value, value_len, tmp); + + return pos; +} + +#endif