lsquic_parse.h revision c51ce338 
1/* Copyright (c) 2017 LiteSpeed Technologies Inc.  See LICENSE. */
2#ifndef LSQUIC_PARSE_H
3#define LSQUIC_PARSE_H 1
4
5#include <stdint.h>
6
7#include "lsquic_packet_common.h"
8
9struct lsquic_packet_in;
10struct stream_frame;
11
12#define LSQUIC_PARSE_ACK_TIMESTAMPS 0
13
14typedef struct ack_info
15{
16    unsigned    n_timestamps;   /* 0 to 255 */
17    unsigned    n_ranges;       /* This is at least 1 */
18                                /* Largest acked is ack_info.ranges[0].high */
19    lsquic_time_t   lack_delta;
20    struct {
21        lsquic_packno_t high, low;
22    }           ranges[256];
23#if LSQUIC_PARSE_ACK_TIMESTAMPS
24    struct {
25        /* Currently we just read these timestamps in (assuming it is
26         * compiled in, of course), but do not do anything with them.
27         * When we do, the representation of these fields should be
28         * switched to whatever is most appropriate/efficient.
29         */
30        unsigned char   packet_delta;
31        uint64_t        delta_usec;
32    }           timestamps[255];
33#endif
34} ack_info_t;
35
36#define largest_acked(acki) (+(acki)->ranges[0].high)
37
38#define smallest_acked(acki) (+(acki)->ranges[(acki)->n_ranges - 1].low)
39
40/* gaf_: generate ACK frame */
41struct lsquic_packno_range;
42typedef const struct lsquic_packno_range *
43    (*gaf_rechist_first_f)          (void *rechist);
44typedef const struct lsquic_packno_range *
45    (*gaf_rechist_next_f)           (void *rechist);
46typedef lsquic_time_t
47    (*gaf_rechist_largest_recv_f)   (void *rechist);
48
49/* gsf_: generate stream frame */
50typedef int    (*gsf_fin_f)  (void *stream);
51typedef size_t (*gsf_size_f) (void *stream);
52typedef size_t (*gsf_read_f) (void *stream, void *buf, size_t len, int *fin);
53
54struct packin_parse_state {
55    const unsigned char     *pps_p;      /* Pointer to packet number */
56    unsigned                 pps_nbytes; /* Number of bytes in packet number */
57};
58
59/* This structure contains functions that parse and generate packets and
60 * frames in version-specific manner.  To begin with, there is difference
61 * between GQUIC's little-endian (Q038 and lower) and big-endian formats
62 * (Q039 and higher).
63 */
64struct parse_funcs
65{
66    int
67    (*pf_gen_ver_nego_pkt) (unsigned char *buf, size_t bufsz, uint64_t conn_id,
68                            unsigned version_bitmask);
69    /* Return buf length */
70    int
71    (*pf_gen_reg_pkt_header) (unsigned char *buf, size_t bufsz,
72                            const lsquic_cid_t *, const lsquic_ver_tag_t *,
73                            const unsigned char *nonce, lsquic_packno_t,
74                            enum lsquic_packno_bits);
75    void
76    (*pf_parse_packet_in_finish) (struct lsquic_packet_in *packet_in,
77                                                struct packin_parse_state *);
78    enum QUIC_FRAME_TYPE
79    (*pf_parse_frame_type) (unsigned char);
80    /* Return used buffer length */
81    int
82    (*pf_gen_stream_frame) (unsigned char *buf, size_t bufsz,
83                            uint32_t stream_id, uint64_t offset,
84                            gsf_fin_f, gsf_size_f, gsf_read_f, void *stream);
85    unsigned
86    (*pf_parse_stream_frame_header_sz) (unsigned char type);
87    int
88    (*pf_parse_stream_frame) (const unsigned char *buf, size_t rem_packet_sz,
89                                                    struct stream_frame *);
90    int
91    (*pf_parse_ack_frame) (const unsigned char *buf, size_t buf_len,
92                                                    ack_info_t *ack_info);
93    lsquic_packno_t
94    (*pf_parse_ack_high) (const unsigned char *buf, size_t buf_len);
95    int
96    (*pf_gen_ack_frame) (unsigned char *outbuf, size_t outbuf_sz,
97                gaf_rechist_first_f, gaf_rechist_next_f,
98                gaf_rechist_largest_recv_f, void *rechist, lsquic_time_t now,
99                int *has_missing);
100    int
101    (*pf_gen_stop_waiting_frame) (unsigned char *buf, size_t buf_len,
102                    lsquic_packno_t cur_packno, enum lsquic_packno_bits,
103                    lsquic_packno_t least_unacked_packno);
104    int
105    (*pf_parse_stop_waiting_frame) (const unsigned char *buf, size_t buf_len,
106                     lsquic_packno_t cur_packno, enum lsquic_packno_bits,
107                     lsquic_packno_t *least_unacked);
108    int
109    (*pf_skip_stop_waiting_frame) (size_t buf_len, enum lsquic_packno_bits);
110    int
111    (*pf_gen_window_update_frame) (unsigned char *buf, int buf_len,
112                                    uint32_t stream_id, uint64_t offset);
113    int
114    (*pf_parse_window_update_frame) (const unsigned char *buf, size_t buf_len,
115                                      uint32_t *stream_id, uint64_t *offset);
116    int
117    (*pf_gen_blocked_frame) (unsigned char *buf, size_t buf_len,
118                                                        uint32_t stream_id);
119    int
120    (*pf_parse_blocked_frame) (const unsigned char *buf, size_t buf_len,
121                                                        uint32_t *stream_id);
122    int
123    (*pf_gen_rst_frame) (unsigned char *buf, size_t buf_len, uint32_t stream_id,
124                          uint64_t offset, uint32_t error_code);
125    int
126    (*pf_parse_rst_frame) (const unsigned char *buf, size_t buf_len,
127                uint32_t *stream_id, uint64_t *offset, uint32_t *error_code);
128    int
129    (*pf_gen_connect_close_frame) (unsigned char *buf, int buf_len,
130                uint32_t error_code, const char *reason, int reason_len);
131    int
132    (*pf_parse_connect_close_frame) (const unsigned char *buf, size_t buf_len,
133                uint32_t *error_code, uint16_t *reason_length,
134                uint8_t *reason_offset);
135    int
136    (*pf_gen_goaway_frame) (unsigned char *buf, size_t buf_len,
137                uint32_t error_code, uint32_t last_good_stream_id,
138                const char *reason, size_t reason_len);
139    int
140    (*pf_parse_goaway_frame) (const unsigned char *buf, size_t buf_len,
141                uint32_t *error_code, uint32_t *last_good_stream_id,
142                uint16_t *reason_length, const char **reason);
143    int
144    (*pf_gen_ping_frame) (unsigned char *buf, int buf_len);
145#ifndef NDEBUG
146    /* These float reading and writing functions assume `mem' has at least
147     * 2 bytes.
148     */
149    void
150    (*pf_write_float_time16) (lsquic_time_t time_us, void *mem);
151    uint64_t
152    (*pf_read_float_time16) (const void *mem);
153#endif
154    size_t
155    (*pf_calc_stream_frame_header_sz) (uint32_t stream_id, uint64_t offset);
156    void
157    (*pf_turn_on_fin) (unsigned char *);
158};
159
160extern const struct parse_funcs lsquic_parse_funcs_gquic_le;
161/* Q039 and later are big-endian: */
162extern const struct parse_funcs lsquic_parse_funcs_gquic_Q039;
163extern const struct parse_funcs lsquic_parse_funcs_gquic_Q041;
164
165#define select_pf_by_ver(ver) (                                         \
166    ((1 << (ver)) & ((1 << LSQVER_035) |                                \
167                     (1 << LSQVER_037) | (1 << LSQVER_038)))            \
168        ? &lsquic_parse_funcs_gquic_le :                                \
169    ((1 << (ver)) & (1 << LSQVER_039))                                  \
170        ? &lsquic_parse_funcs_gquic_Q039                                \
171        : &lsquic_parse_funcs_gquic_Q041)
172
173/* This function is QUIC-version independent */
174int
175parse_packet_in_begin (struct lsquic_packet_in *, size_t length,
176                                int is_server, struct packin_parse_state *);
177
178enum QUIC_FRAME_TYPE
179parse_frame_type_gquic_Q035_thru_Q039 (unsigned char first_byte);
180
181enum QUIC_FRAME_TYPE
182parse_frame_type_gquic_Q041 (unsigned char first_byte);
183
184unsigned
185parse_stream_frame_header_sz_gquic (unsigned char type);
186
187size_t
188calc_stream_frame_header_sz_gquic (uint32_t stream_id, uint64_t offset);
189
190/* This maps two bits as follows:
191 *  00  ->  1
192 *  01  ->  2
193 *  10  ->  4
194 *  11  ->  6
195 *
196 * Assumes that only two low bits are set.
197 */
198#define twobit_to_1246(bits) ((bits) * 2 + !(bits))
199
200/* This maps two bits as follows:
201 *  00  ->  1
202 *  01  ->  2
203 *  10  ->  4
204 *  11  ->  8
205 *
206 * Assumes that only two low bits are set.
207 */
208#define twobit_to_1248(bits) (1 << (bits))
209
210char *
211acki2str (const struct ack_info *acki, size_t *sz);
212
213void
214lsquic_turn_on_fin_Q035_thru_Q039 (unsigned char *);
215
216#endif
217