| // Copyright 2014 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package hpack |
| |
| import ( |
| "fmt" |
| ) |
| |
| // headerFieldTable implements a list of HeaderFields. |
| // This is used to implement the static and dynamic tables. |
| type headerFieldTable struct { |
| // For static tables, entries are never evicted. |
| // |
| // For dynamic tables, entries are evicted from ents[0] and added to the end. |
| // Each entry has a unique id that starts at one and increments for each |
| // entry that is added. This unique id is stable across evictions, meaning |
| // it can be used as a pointer to a specific entry. As in hpack, unique ids |
| // are 1-based. The unique id for ents[k] is k + evictCount + 1. |
| // |
| // Zero is not a valid unique id. |
| // |
| // evictCount should not overflow in any remotely practical situation. In |
| // practice, we will have one dynamic table per HTTP/2 connection. If we |
| // assume a very powerful server that handles 1M QPS per connection and each |
| // request adds (then evicts) 100 entries from the table, it would still take |
| // 2M years for evictCount to overflow. |
| ents []HeaderField |
| evictCount uint64 |
| |
| // byName maps a HeaderField name to the unique id of the newest entry with |
| // the same name. See above for a definition of "unique id". |
| byName map[string]uint64 |
| |
| // byNameValue maps a HeaderField name/value pair to the unique id of the newest |
| // entry with the same name and value. See above for a definition of "unique id". |
| byNameValue map[pairNameValue]uint64 |
| } |
| |
| type pairNameValue struct { |
| name, value string |
| } |
| |
| func (t *headerFieldTable) init() { |
| t.byName = make(map[string]uint64) |
| t.byNameValue = make(map[pairNameValue]uint64) |
| } |
| |
| // len reports the number of entries in the table. |
| func (t *headerFieldTable) len() int { |
| return len(t.ents) |
| } |
| |
| // addEntry adds a new entry. |
| func (t *headerFieldTable) addEntry(f HeaderField) { |
| id := uint64(t.len()) + t.evictCount + 1 |
| t.byName[f.Name] = id |
| t.byNameValue[pairNameValue{f.Name, f.Value}] = id |
| t.ents = append(t.ents, f) |
| } |
| |
| // evictOldest evicts the n oldest entries in the table. |
| func (t *headerFieldTable) evictOldest(n int) { |
| if n > t.len() { |
| panic(fmt.Sprintf("evictOldest(%v) on table with %v entries", n, t.len())) |
| } |
| for k := 0; k < n; k++ { |
| f := t.ents[k] |
| id := t.evictCount + uint64(k) + 1 |
| if t.byName[f.Name] == id { |
| delete(t.byName, f.Name) |
| } |
| if p := (pairNameValue{f.Name, f.Value}); t.byNameValue[p] == id { |
| delete(t.byNameValue, p) |
| } |
| } |
| copy(t.ents, t.ents[n:]) |
| for k := t.len() - n; k < t.len(); k++ { |
| t.ents[k] = HeaderField{} // so strings can be garbage collected |
| } |
| t.ents = t.ents[:t.len()-n] |
| if t.evictCount+uint64(n) < t.evictCount { |
| panic("evictCount overflow") |
| } |
| t.evictCount += uint64(n) |
| } |
| |
| // search finds f in the table. If there is no match, i is 0. |
| // If both name and value match, i is the matched index and nameValueMatch |
| // becomes true. If only name matches, i points to that index and |
| // nameValueMatch becomes false. |
| // |
| // The returned index is a 1-based HPACK index. For dynamic tables, HPACK says |
| // that index 1 should be the newest entry, but t.ents[0] is the oldest entry, |
| // meaning t.ents is reversed for dynamic tables. Hence, when t is a dynamic |
| // table, the return value i actually refers to the entry t.ents[t.len()-i]. |
| // |
| // All tables are assumed to be a dynamic tables except for the global |
| // staticTable pointer. |
| // |
| // See Section 2.3.3. |
| func (t *headerFieldTable) search(f HeaderField) (i uint64, nameValueMatch bool) { |
| if !f.Sensitive { |
| if id := t.byNameValue[pairNameValue{f.Name, f.Value}]; id != 0 { |
| return t.idToIndex(id), true |
| } |
| } |
| if id := t.byName[f.Name]; id != 0 { |
| return t.idToIndex(id), false |
| } |
| return 0, false |
| } |
| |
| // idToIndex converts a unique id to an HPACK index. |
| // See Section 2.3.3. |
| func (t *headerFieldTable) idToIndex(id uint64) uint64 { |
| if id <= t.evictCount { |
| panic(fmt.Sprintf("id (%v) <= evictCount (%v)", id, t.evictCount)) |
| } |
| k := id - t.evictCount - 1 // convert id to an index t.ents[k] |
| if t != staticTable { |
| return uint64(t.len()) - k // dynamic table |
| } |
| return k + 1 |
| } |
| |
| // http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-07#appendix-B |
| var staticTable = newStaticTable() |
| var staticTableEntries = [...]HeaderField{ |
| HeaderField{Name: ":authority"}, |
| HeaderField{Name: ":method", Value: "GET"}, |
| HeaderField{Name: ":method", Value: "POST"}, |
| HeaderField{Name: ":path", Value: "/"}, |
| HeaderField{Name: ":path", Value: "/index.html"}, |
| HeaderField{Name: ":scheme", Value: "http"}, |
| HeaderField{Name: ":scheme", Value: "https"}, |
| HeaderField{Name: ":status", Value: "200"}, |
| HeaderField{Name: ":status", Value: "204"}, |
| HeaderField{Name: ":status", Value: "206"}, |
| HeaderField{Name: ":status", Value: "304"}, |
| HeaderField{Name: ":status", Value: "400"}, |
| HeaderField{Name: ":status", Value: "404"}, |
| HeaderField{Name: ":status", Value: "500"}, |
| HeaderField{Name: "accept-charset"}, |
| HeaderField{Name: "accept-encoding", Value: "gzip, deflate"}, |
| HeaderField{Name: "accept-language"}, |
| HeaderField{Name: "accept-ranges"}, |
| HeaderField{Name: "accept"}, |
| HeaderField{Name: "access-control-allow-origin"}, |
| HeaderField{Name: "age"}, |
| HeaderField{Name: "allow"}, |
| HeaderField{Name: "authorization"}, |
| HeaderField{Name: "cache-control"}, |
| HeaderField{Name: "content-disposition"}, |
| HeaderField{Name: "content-encoding"}, |
| HeaderField{Name: "content-language"}, |
| HeaderField{Name: "content-length"}, |
| HeaderField{Name: "content-location"}, |
| HeaderField{Name: "content-range"}, |
| HeaderField{Name: "content-type"}, |
| HeaderField{Name: "cookie"}, |
| HeaderField{Name: "date"}, |
| HeaderField{Name: "etag"}, |
| HeaderField{Name: "expect"}, |
| HeaderField{Name: "expires"}, |
| HeaderField{Name: "from"}, |
| HeaderField{Name: "host"}, |
| HeaderField{Name: "if-match"}, |
| HeaderField{Name: "if-modified-since"}, |
| HeaderField{Name: "if-none-match"}, |
| HeaderField{Name: "if-range"}, |
| HeaderField{Name: "if-unmodified-since"}, |
| HeaderField{Name: "last-modified"}, |
| HeaderField{Name: "link"}, |
| HeaderField{Name: "location"}, |
| HeaderField{Name: "max-forwards"}, |
| HeaderField{Name: "proxy-authenticate"}, |
| HeaderField{Name: "proxy-authorization"}, |
| HeaderField{Name: "range"}, |
| HeaderField{Name: "referer"}, |
| HeaderField{Name: "refresh"}, |
| HeaderField{Name: "retry-after"}, |
| HeaderField{Name: "server"}, |
| HeaderField{Name: "set-cookie"}, |
| HeaderField{Name: "strict-transport-security"}, |
| HeaderField{Name: "transfer-encoding"}, |
| HeaderField{Name: "user-agent"}, |
| HeaderField{Name: "vary"}, |
| HeaderField{Name: "via"}, |
| HeaderField{Name: "www-authenticate"}, |
| } |
| |
| func newStaticTable() *headerFieldTable { |
| t := &headerFieldTable{} |
| t.init() |
| for _, e := range staticTableEntries[:] { |
| t.addEntry(e) |
| } |
| return t |
| } |
| |
| var huffmanCodes = [256]uint32{ |
| 0x1ff8, |
| 0x7fffd8, |
| 0xfffffe2, |
| 0xfffffe3, |
| 0xfffffe4, |
| 0xfffffe5, |
| 0xfffffe6, |
| 0xfffffe7, |
| 0xfffffe8, |
| 0xffffea, |
| 0x3ffffffc, |
| 0xfffffe9, |
| 0xfffffea, |
| 0x3ffffffd, |
| 0xfffffeb, |
| 0xfffffec, |
| 0xfffffed, |
| 0xfffffee, |
| 0xfffffef, |
| 0xffffff0, |
| 0xffffff1, |
| 0xffffff2, |
| 0x3ffffffe, |
| 0xffffff3, |
| 0xffffff4, |
| 0xffffff5, |
| 0xffffff6, |
| 0xffffff7, |
| 0xffffff8, |
| 0xffffff9, |
| 0xffffffa, |
| 0xffffffb, |
| 0x14, |
| 0x3f8, |
| 0x3f9, |
| 0xffa, |
| 0x1ff9, |
| 0x15, |
| 0xf8, |
| 0x7fa, |
| 0x3fa, |
| 0x3fb, |
| 0xf9, |
| 0x7fb, |
| 0xfa, |
| 0x16, |
| 0x17, |
| 0x18, |
| 0x0, |
| 0x1, |
| 0x2, |
| 0x19, |
| 0x1a, |
| 0x1b, |
| 0x1c, |
| 0x1d, |
| 0x1e, |
| 0x1f, |
| 0x5c, |
| 0xfb, |
| 0x7ffc, |
| 0x20, |
| 0xffb, |
| 0x3fc, |
| 0x1ffa, |
| 0x21, |
| 0x5d, |
| 0x5e, |
| 0x5f, |
| 0x60, |
| 0x61, |
| 0x62, |
| 0x63, |
| 0x64, |
| 0x65, |
| 0x66, |
| 0x67, |
| 0x68, |
| 0x69, |
| 0x6a, |
| 0x6b, |
| 0x6c, |
| 0x6d, |
| 0x6e, |
| 0x6f, |
| 0x70, |
| 0x71, |
| 0x72, |
| 0xfc, |
| 0x73, |
| 0xfd, |
| 0x1ffb, |
| 0x7fff0, |
| 0x1ffc, |
| 0x3ffc, |
| 0x22, |
| 0x7ffd, |
| 0x3, |
| 0x23, |
| 0x4, |
| 0x24, |
| 0x5, |
| 0x25, |
| 0x26, |
| 0x27, |
| 0x6, |
| 0x74, |
| 0x75, |
| 0x28, |
| 0x29, |
| 0x2a, |
| 0x7, |
| 0x2b, |
| 0x76, |
| 0x2c, |
| 0x8, |
| 0x9, |
| 0x2d, |
| 0x77, |
| 0x78, |
| 0x79, |
| 0x7a, |
| 0x7b, |
| 0x7ffe, |
| 0x7fc, |
| 0x3ffd, |
| 0x1ffd, |
| 0xffffffc, |
| 0xfffe6, |
| 0x3fffd2, |
| 0xfffe7, |
| 0xfffe8, |
| 0x3fffd3, |
| 0x3fffd4, |
| 0x3fffd5, |
| 0x7fffd9, |
| 0x3fffd6, |
| 0x7fffda, |
| 0x7fffdb, |
| 0x7fffdc, |
| 0x7fffdd, |
| 0x7fffde, |
| 0xffffeb, |
| 0x7fffdf, |
| 0xffffec, |
| 0xffffed, |
| 0x3fffd7, |
| 0x7fffe0, |
| 0xffffee, |
| 0x7fffe1, |
| 0x7fffe2, |
| 0x7fffe3, |
| 0x7fffe4, |
| 0x1fffdc, |
| 0x3fffd8, |
| 0x7fffe5, |
| 0x3fffd9, |
| 0x7fffe6, |
| 0x7fffe7, |
| 0xffffef, |
| 0x3fffda, |
| 0x1fffdd, |
| 0xfffe9, |
| 0x3fffdb, |
| 0x3fffdc, |
| 0x7fffe8, |
| 0x7fffe9, |
| 0x1fffde, |
| 0x7fffea, |
| 0x3fffdd, |
| 0x3fffde, |
| 0xfffff0, |
| 0x1fffdf, |
| 0x3fffdf, |
| 0x7fffeb, |
| 0x7fffec, |
| 0x1fffe0, |
| 0x1fffe1, |
| 0x3fffe0, |
| 0x1fffe2, |
| 0x7fffed, |
| 0x3fffe1, |
| 0x7fffee, |
| 0x7fffef, |
| 0xfffea, |
| 0x3fffe2, |
| 0x3fffe3, |
| 0x3fffe4, |
| 0x7ffff0, |
| 0x3fffe5, |
| 0x3fffe6, |
| 0x7ffff1, |
| 0x3ffffe0, |
| 0x3ffffe1, |
| 0xfffeb, |
| 0x7fff1, |
| 0x3fffe7, |
| 0x7ffff2, |
| 0x3fffe8, |
| 0x1ffffec, |
| 0x3ffffe2, |
| 0x3ffffe3, |
| 0x3ffffe4, |
| 0x7ffffde, |
| 0x7ffffdf, |
| 0x3ffffe5, |
| 0xfffff1, |
| 0x1ffffed, |
| 0x7fff2, |
| 0x1fffe3, |
| 0x3ffffe6, |
| 0x7ffffe0, |
| 0x7ffffe1, |
| 0x3ffffe7, |
| 0x7ffffe2, |
| 0xfffff2, |
| 0x1fffe4, |
| 0x1fffe5, |
| 0x3ffffe8, |
| 0x3ffffe9, |
| 0xffffffd, |
| 0x7ffffe3, |
| 0x7ffffe4, |
| 0x7ffffe5, |
| 0xfffec, |
| 0xfffff3, |
| 0xfffed, |
| 0x1fffe6, |
| 0x3fffe9, |
| 0x1fffe7, |
| 0x1fffe8, |
| 0x7ffff3, |
| 0x3fffea, |
| 0x3fffeb, |
| 0x1ffffee, |
| 0x1ffffef, |
| 0xfffff4, |
| 0xfffff5, |
| 0x3ffffea, |
| 0x7ffff4, |
| 0x3ffffeb, |
| 0x7ffffe6, |
| 0x3ffffec, |
| 0x3ffffed, |
| 0x7ffffe7, |
| 0x7ffffe8, |
| 0x7ffffe9, |
| 0x7ffffea, |
| 0x7ffffeb, |
| 0xffffffe, |
| 0x7ffffec, |
| 0x7ffffed, |
| 0x7ffffee, |
| 0x7ffffef, |
| 0x7fffff0, |
| 0x3ffffee, |
| } |
| |
| var huffmanCodeLen = [256]uint8{ |
| 13, 23, 28, 28, 28, 28, 28, 28, 28, 24, 30, 28, 28, 30, 28, 28, |
| 28, 28, 28, 28, 28, 28, 30, 28, 28, 28, 28, 28, 28, 28, 28, 28, |
| 6, 10, 10, 12, 13, 6, 8, 11, 10, 10, 8, 11, 8, 6, 6, 6, |
| 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 7, 8, 15, 6, 12, 10, |
| 13, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, |
| 7, 7, 7, 7, 7, 7, 7, 7, 8, 7, 8, 13, 19, 13, 14, 6, |
| 15, 5, 6, 5, 6, 5, 6, 6, 6, 5, 7, 7, 6, 6, 6, 5, |
| 6, 7, 6, 5, 5, 6, 7, 7, 7, 7, 7, 15, 11, 14, 13, 28, |
| 20, 22, 20, 20, 22, 22, 22, 23, 22, 23, 23, 23, 23, 23, 24, 23, |
| 24, 24, 22, 23, 24, 23, 23, 23, 23, 21, 22, 23, 22, 23, 23, 24, |
| 22, 21, 20, 22, 22, 23, 23, 21, 23, 22, 22, 24, 21, 22, 23, 23, |
| 21, 21, 22, 21, 23, 22, 23, 23, 20, 22, 22, 22, 23, 22, 22, 23, |
| 26, 26, 20, 19, 22, 23, 22, 25, 26, 26, 26, 27, 27, 26, 24, 25, |
| 19, 21, 26, 27, 27, 26, 27, 24, 21, 21, 26, 26, 28, 27, 27, 27, |
| 20, 24, 20, 21, 22, 21, 21, 23, 22, 22, 25, 25, 24, 24, 26, 23, |
| 26, 27, 26, 26, 27, 27, 27, 27, 27, 28, 27, 27, 27, 27, 27, 26, |
| } |