diff options
Diffstat (limited to 'src/qpack-enc.c')
| -rw-r--r-- | src/qpack-enc.c | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/src/qpack-enc.c b/src/qpack-enc.c new file mode 100644 index 0000000..006f1f1 --- /dev/null +++ b/src/qpack-enc.c @@ -0,0 +1,185 @@ +#include <haproxy/qpack-enc.h> + +#include <haproxy/buf.h> +#include <haproxy/intops.h> + +/* Returns the byte size required to encode <i> as a <prefix_size>-prefix + * integer. + */ +static size_t qpack_get_prefix_int_size(int i, int prefix_size) +{ + int n = (1 << prefix_size) - 1; + if (i < n) { + return 1; + } + else { + size_t result = 0; + while (i) { + ++result; + i >>= 7; + } + return 1 + result; + } +} + +/* Encode the integer <i> in the buffer <out> in a <prefix_size>-bit prefix + * integer. The caller must ensure there is enough size in the buffer. The + * prefix is OR-ed with <before_prefix> byte. + * + * Returns 0 if success else non-zero. + */ +static int qpack_encode_prefix_integer(struct buffer *out, int i, + int prefix_size, + unsigned char before_prefix) +{ + const int mod = (1 << prefix_size) - 1; + BUG_ON_HOT(!prefix_size); + + if (i < mod) { + if (b_room(out) < 1) + return 1; + + b_putchr(out, before_prefix | i); + } + else { + int to_encode = i - mod; + const size_t sz = to_encode / mod; + + if (b_room(out) < sz) + return 1; + + b_putchr(out, before_prefix | mod); + while (1) { + if (to_encode > 0x7f) { + b_putchr(out, 0x80 | (to_encode & 0x7f)); + to_encode >>= 7; + } + else { + b_putchr(out, to_encode & 0x7f); + break; + } + } + } + + return 0; +} + +/* Returns 0 on success else non-zero. */ +int qpack_encode_int_status(struct buffer *out, unsigned int status) +{ + int status_size, idx = 0; + + if (status < 100 || status > 999) + return 1; + + switch (status) { + case 103: idx = 24; break; + case 200: idx = 25; break; + case 304: idx = 26; break; + case 404: idx = 27; break; + case 503: idx = 28; break; + case 100: idx = 63; break; + case 204: idx = 64; break; + case 206: idx = 65; break; + case 302: idx = 66; break; + case 400: idx = 67; break; + case 403: idx = 68; break; + case 421: idx = 69; break; + case 425: idx = 70; break; + case 500: idx = 71; break; + + /* status code not in QPACK static table, idx is null. */ + default: break; + } + + if (idx) { + /* status code present in QPACK static table + * -> indexed field line + */ + status_size = qpack_get_prefix_int_size(idx, 6); + if (b_room(out) < status_size) + return 1; + + qpack_encode_prefix_integer(out, idx, 6, 0xc0); + } + else { + /* status code not present in QPACK static table + * -> literal field line with name reference + */ + char a, b, c; + a = '0' + status / 100; + status -= (status / 100 * 100); + b = '0' + status / 10; + status -= (status / 10 * 10); + c = '0' + status; + + /* field name */ + if (qpack_encode_prefix_integer(out, 24, 4, 0x50)) + return 1; + + /* field value length */ + if (qpack_encode_prefix_integer(out, 3, 7, 0x00)) + return 1; + + if (b_room(out) < 3) + return 1; + + b_putchr(out, a); + b_putchr(out, b); + b_putchr(out, c); + } + + return 0; +} + +/* Returns 0 on success else non-zero. */ +int qpack_encode_field_section_line(struct buffer *out) +{ + char qpack_field_section[] = { + '\x00', /* required insert count */ + '\x00', /* S + delta base */ + }; + + if (b_room(out) < 2) + return 1; + + b_putblk(out, qpack_field_section, 2); + + return 0; +} + +#define QPACK_LFL_WLN_BIT 0x20 // Literal field line with literal name + +/* Encode a header in literal field line with literal name. + * Returns 0 on success else non-zero. + */ +int qpack_encode_header(struct buffer *out, const struct ist n, const struct ist v) +{ + int i; + size_t sz = qpack_get_prefix_int_size(n.len, 3) + n.len + + qpack_get_prefix_int_size(v.len, 7) + v.len; + + if (sz > b_room(out)) + return 1; + + /* literal field line with literal name + * | 0 | 0 | 1 | N | H | . | . | . | + * N :(allow an intermediary to add the header in a dynamic table) + * H: huffman encoded + * name len + */ + qpack_encode_prefix_integer(out, n.len, 3, QPACK_LFL_WLN_BIT); + /* name */ + for (i = 0; i < n.len; ++i) + b_putchr(out, n.ptr[i]); + + /* | 0 | . | . | . | . | . | . | . | + * value len + */ + qpack_encode_prefix_integer(out, v.len, 7, 0x00); + /* value */ + for (i = 0; i < v.len; ++i) + b_putchr(out, v.ptr[i]); + + return 0; +} |