lsquic_parse.h revision c95974e9 
1/* Copyright (c) 2017 - 2018 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 lsquic_packno_range ranges[256];
21#if LSQUIC_PARSE_ACK_TIMESTAMPS
22    struct {
23        /* Currently we just read these timestamps in (assuming it is
24         * compiled in, of course), but do not do anything with them.
25         * When we do, the representation of these fields should be
26         * switched to whatever is most appropriate/efficient.
27         */
28        unsigned char   packet_delta;
29        uint64_t        delta_usec;
30    }           timestamps[255];
31#endif
32} ack_info_t;
33
34struct short_ack_info
35{
36    unsigned                    sai_n_timestamps;
37    lsquic_time_t               sai_lack_delta;
38    struct lsquic_packno_range  sai_range;
39};
40
41#define largest_acked(acki) (+(acki)->ranges[0].high)
42
43#define smallest_acked(acki) (+(acki)->ranges[(acki)->n_ranges - 1].low)
44
45/* gaf_: generate ACK frame */
46struct lsquic_packno_range;
47typedef const struct lsquic_packno_range *
48    (*gaf_rechist_first_f)          (void *rechist);
49typedef const struct lsquic_packno_range *
50    (*gaf_rechist_next_f)           (void *rechist);
51typedef lsquic_time_t
52    (*gaf_rechist_largest_recv_f)   (void *rechist);
53
54/* gsf_: generate stream frame */
55typedef size_t (*gsf_read_f) (void *stream, void *buf, size_t len, int *fin);
56
57struct packin_parse_state {
58    const unsigned char     *pps_p;      /* Pointer to packet number */
59    unsigned                 pps_nbytes; /* Number of bytes in packet number */
60};
61
62/* This structure contains functions that parse and generate packets and
63 * frames in version-specific manner.  To begin with, there is difference
64 * between GQUIC's little-endian (Q038 and lower) and big-endian formats
65 * (Q039 and higher).
66 */
67struct parse_funcs
68{
69    int
70    (*pf_gen_ver_nego_pkt) (unsigned char *buf, size_t bufsz, uint64_t conn_id,
71                            unsigned version_bitmask);
72    /* Return buf length */
73    int
74    (*pf_gen_reg_pkt_header) (unsigned char *buf, size_t bufsz,
75                            const lsquic_cid_t *, const lsquic_ver_tag_t *,
76                            const unsigned char *nonce, lsquic_packno_t,
77                            enum lsquic_packno_bits);
78    void
79    (*pf_parse_packet_in_finish) (struct lsquic_packet_in *packet_in,
80                                                struct packin_parse_state *);
81    enum QUIC_FRAME_TYPE
82    (*pf_parse_frame_type) (unsigned char);
83    /* Return used buffer length */
84    int
85    (*pf_gen_stream_frame) (unsigned char *buf, size_t bufsz,
86                            uint32_t stream_id, uint64_t offset,
87                            int fin, size_t size, gsf_read_f, void *stream);
88    unsigned
89    (*pf_parse_stream_frame_header_sz) (unsigned char type);
90    int
91    (*pf_parse_stream_frame) (const unsigned char *buf, size_t rem_packet_sz,
92                                                    struct stream_frame *);
93    int
94    (*pf_parse_ack_frame) (const unsigned char *buf, size_t buf_len,
95                                                    ack_info_t *ack_info);
96    int
97    (*pf_gen_ack_frame) (unsigned char *outbuf, size_t outbuf_sz,
98                gaf_rechist_first_f, gaf_rechist_next_f,
99                gaf_rechist_largest_recv_f, void *rechist, lsquic_time_t now,
100                int *has_missing, lsquic_packno_t *largest_received);
101    int
102    (*pf_gen_stop_waiting_frame) (unsigned char *buf, size_t buf_len,
103                    lsquic_packno_t cur_packno, enum lsquic_packno_bits,
104                    lsquic_packno_t least_unacked_packno);
105    int
106    (*pf_parse_stop_waiting_frame) (const unsigned char *buf, size_t buf_len,
107                     lsquic_packno_t cur_packno, enum lsquic_packno_bits,
108                     lsquic_packno_t *least_unacked);
109    int
110    (*pf_skip_stop_waiting_frame) (size_t buf_len, enum lsquic_packno_bits);
111    int
112    (*pf_gen_window_update_frame) (unsigned char *buf, int buf_len,
113                                    uint32_t stream_id, uint64_t offset);
114    int
115    (*pf_parse_window_update_frame) (const unsigned char *buf, size_t buf_len,
116                                      uint32_t *stream_id, uint64_t *offset);
117    int
118    (*pf_gen_blocked_frame) (unsigned char *buf, size_t buf_len,
119                                                        uint32_t stream_id);
120    int
121    (*pf_parse_blocked_frame) (const unsigned char *buf, size_t buf_len,
122                                                        uint32_t *stream_id);
123    int
124    (*pf_gen_rst_frame) (unsigned char *buf, size_t buf_len, uint32_t stream_id,
125                          uint64_t offset, uint32_t error_code);
126    int
127    (*pf_parse_rst_frame) (const unsigned char *buf, size_t buf_len,
128                uint32_t *stream_id, uint64_t *offset, uint32_t *error_code);
129    int
130    (*pf_gen_connect_close_frame) (unsigned char *buf, int buf_len,
131                uint32_t error_code, const char *reason, int reason_len);
132    int
133    (*pf_parse_connect_close_frame) (const unsigned char *buf, size_t buf_len,
134                uint32_t *error_code, uint16_t *reason_length,
135                uint8_t *reason_offset);
136    int
137    (*pf_gen_goaway_frame) (unsigned char *buf, size_t buf_len,
138                uint32_t error_code, uint32_t last_good_stream_id,
139                const char *reason, size_t reason_len);
140    int
141    (*pf_parse_goaway_frame) (const unsigned char *buf, size_t buf_len,
142                uint32_t *error_code, uint32_t *last_good_stream_id,
143                uint16_t *reason_length, const char **reason);
144    int
145    (*pf_gen_ping_frame) (unsigned char *buf, int buf_len);
146#ifndef NDEBUG
147    /* These float reading and writing functions assume `mem' has at least
148     * 2 bytes.
149     */
150    void
151    (*pf_write_float_time16) (lsquic_time_t time_us, void *mem);
152    uint64_t
153    (*pf_read_float_time16) (const void *mem);
154#endif
155    size_t
156    (*pf_calc_stream_frame_header_sz) (uint32_t stream_id, uint64_t offset);
157    void
158    (*pf_turn_on_fin) (unsigned char *);
159};
160
161extern const struct parse_funcs lsquic_parse_funcs_gquic_le;
162/* Q039 and later are big-endian: */
163extern const struct parse_funcs lsquic_parse_funcs_gquic_Q039;
164extern const struct parse_funcs lsquic_parse_funcs_gquic_Q041;
165
166#define select_pf_by_ver(ver) (                                         \
167    ((1 << (ver)) & ((1 << LSQVER_035) |                                \
168                     (1 << LSQVER_037) | (1 << LSQVER_038)))            \
169        ? &lsquic_parse_funcs_gquic_le :                                \
170    ((1 << (ver)) & (1 << LSQVER_041))                                  \
171        ? &lsquic_parse_funcs_gquic_Q041                                \
172        : &lsquic_parse_funcs_gquic_Q039)
173
174/* This function is QUIC-version independent */
175int
176parse_packet_in_begin (struct lsquic_packet_in *, size_t length,
177                                int is_server, struct packin_parse_state *);
178
179enum QUIC_FRAME_TYPE
180parse_frame_type_gquic_Q035_thru_Q039 (unsigned char first_byte);
181
182enum QUIC_FRAME_TYPE
183parse_frame_type_gquic_Q041 (unsigned char first_byte);
184
185unsigned
186parse_stream_frame_header_sz_gquic (unsigned char type);
187
188size_t
189calc_stream_frame_header_sz_gquic (uint32_t stream_id, uint64_t offset);
190
191/* This maps two bits as follows:
192 *  00  ->  1
193 *  01  ->  2
194 *  10  ->  4
195 *  11  ->  6
196 *
197 * Assumes that only two low bits are set.
198 */
199#define twobit_to_1246(bits) ((bits) * 2 + !(bits))
200
201/* This maps two bits as follows:
202 *  00  ->  1
203 *  01  ->  2
204 *  10  ->  4
205 *  11  ->  8
206 *
207 * Assumes that only two low bits are set.
208 */
209#define twobit_to_1248(bits) (1 << (bits))
210
211char *
212acki2str (const struct ack_info *acki, size_t *sz);
213
214void
215lsquic_turn_on_fin_Q035_thru_Q039 (unsigned char *);
216
217#endif
218