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1 /* | 1 /* |
2 * rdbx.h | 2 * rdbx.h |
3 * | 3 * |
4 * replay database with extended packet indices, using a rollover counter | 4 * replay database with extended packet indices, using a rollover counter |
5 * | 5 * |
6 * David A. McGrew | 6 * David A. McGrew |
7 * Cisco Systems, Inc. | 7 * Cisco Systems, Inc. |
8 * | 8 * |
9 */ | 9 */ |
10 | 10 |
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43 * OF THE POSSIBILITY OF SUCH DAMAGE. | 43 * OF THE POSSIBILITY OF SUCH DAMAGE. |
44 * | 44 * |
45 */ | 45 */ |
46 | 46 |
47 #ifndef RDBX_H | 47 #ifndef RDBX_H |
48 #define RDBX_H | 48 #define RDBX_H |
49 | 49 |
50 #include "datatypes.h" | 50 #include "datatypes.h" |
51 #include "err.h" | 51 #include "err.h" |
52 | 52 |
53 /** | 53 #ifdef __cplusplus |
54 * Compatibility shim for v1->v2 transition. | 54 extern "C" { |
55 */ | 55 #endif |
56 | 56 |
57 #define srtp_rdbx_get_packet_index rdbx_get_packet_index | 57 /* #define ROC_TEST */ |
58 | |
59 /* #define ROC_TEST */ | |
60 | 58 |
61 #ifndef ROC_TEST | 59 #ifndef ROC_TEST |
62 | 60 |
63 typedef uint16_t sequence_number_t; /* 16 bit sequence number */ | 61 typedef uint16_t srtp_sequence_number_t; /* 16 bit sequence number */ |
64 typedef uint32_t rollover_counter_t; /* 32 bit rollover counter */ | 62 typedef uint32_t srtp_rollover_counter_t; /* 32 bit rollover counter */ |
65 | 63 |
66 #else /* use small seq_num and roc datatypes for testing purposes */ | 64 #else /* use small seq_num and roc datatypes for testing purposes */ |
67 | 65 |
68 typedef unsigned char sequence_number_t; /* 8 bit sequence number */ | 66 typedef unsigned char srtp_sequence_number_t; /* 8 bit sequence number */ |
69 typedef uint16_t rollover_counter_t; /* 16 bit rollover counter */ | 67 typedef uint16_t srtp_rollover_counter_t; /* 16 bit rollover counter */ |
70 | 68 |
71 #endif | 69 #endif |
72 | 70 |
73 #define seq_num_median (1 << (8*sizeof(sequence_number_t) - 1)) | 71 #define seq_num_median (1 << (8 * sizeof(srtp_sequence_number_t) - 1)) |
74 #define seq_num_max (1 << (8*sizeof(sequence_number_t))) | 72 #define seq_num_max (1 << (8 * sizeof(srtp_sequence_number_t))) |
75 | 73 |
76 /* | 74 /* |
77 * An xtd_seq_num_t is a 64-bit unsigned integer used as an 'extended' | 75 * An rtp_xtd_seq_num_t is a 64-bit unsigned integer used as an 'extended' |
78 * sequence number. | 76 * sequence number. |
79 */ | 77 */ |
80 | 78 typedef uint64_t srtp_xtd_seq_num_t; |
81 typedef uint64_t xtd_seq_num_t; | |
82 | 79 |
83 | 80 |
84 /* | 81 /* |
85 * An rdbx_t is a replay database with extended range; it uses an | 82 * An srtp_rdbx_t is a replay database with extended range; it uses an |
86 * xtd_seq_num_t and a bitmask of recently received indices. | 83 * xtd_seq_num_t and a bitmask of recently received indices. |
87 */ | 84 */ |
88 | |
89 typedef struct { | 85 typedef struct { |
90 xtd_seq_num_t index; | 86 srtp_xtd_seq_num_t index; |
91 bitvector_t bitmask; | 87 bitvector_t bitmask; |
92 } rdbx_t; | 88 } srtp_rdbx_t; |
93 | 89 |
94 | 90 |
95 /* | 91 /* |
96 * rdbx_init(rdbx_ptr, ws) | 92 * srtp_rdbx_init(rdbx_ptr, ws) |
97 * | 93 * |
98 * initializes the rdbx pointed to by its argument with the window size ws, | 94 * initializes the rdbx pointed to by its argument with the window size ws, |
99 * setting the rollover counter and sequence number to zero | 95 * setting the rollover counter and sequence number to zero |
100 */ | 96 */ |
101 | 97 srtp_err_status_t srtp_rdbx_init(srtp_rdbx_t *rdbx, unsigned long ws); |
102 err_status_t | |
103 rdbx_init(rdbx_t *rdbx, unsigned long ws); | |
104 | 98 |
105 | 99 |
106 /* | 100 /* |
107 * rdbx_dealloc(rdbx_ptr) | 101 * srtp_rdbx_dealloc(rdbx_ptr) |
108 * | 102 * |
109 * frees memory associated with the rdbx | 103 * frees memory associated with the rdbx |
110 */ | 104 */ |
111 | 105 srtp_err_status_t srtp_rdbx_dealloc(srtp_rdbx_t *rdbx); |
112 err_status_t | |
113 rdbx_dealloc(rdbx_t *rdbx); | |
114 | 106 |
115 | 107 |
116 /* | 108 /* |
117 * rdbx_estimate_index(rdbx, guess, s) | 109 * srtp_rdbx_estimate_index(rdbx, guess, s) |
118 * | 110 * |
119 * given an rdbx and a sequence number s (from a newly arrived packet), | 111 * given an rdbx and a sequence number s (from a newly arrived packet), |
120 * sets the contents of *guess to contain the best guess of the packet | 112 * sets the contents of *guess to contain the best guess of the packet |
121 * index to which s corresponds, and returns the difference between | 113 * index to which s corresponds, and returns the difference between |
122 * *guess and the locally stored synch info | 114 * *guess and the locally stored synch info |
123 */ | 115 */ |
124 | 116 int srtp_rdbx_estimate_index(const srtp_rdbx_t *rdbx, srtp_xtd_seq_num_t *guess,
srtp_sequence_number_t s); |
125 int | |
126 rdbx_estimate_index(const rdbx_t *rdbx, | |
127 » » xtd_seq_num_t *guess, | |
128 » » sequence_number_t s); | |
129 | 117 |
130 /* | 118 /* |
131 * rdbx_check(rdbx, delta); | 119 * srtp_rdbx_check(rdbx, delta); |
132 * | 120 * |
133 * rdbx_check(&r, delta) checks to see if the xtd_seq_num_t | 121 * srtp_rdbx_check(&r, delta) checks to see if the xtd_seq_num_t |
134 * which is at rdbx->window_start + delta is in the rdb | 122 * which is at rdbx->window_start + delta is in the rdb |
135 * | 123 * |
136 */ | 124 */ |
137 | 125 srtp_err_status_t srtp_rdbx_check(const srtp_rdbx_t *rdbx, int difference); |
138 err_status_t | |
139 rdbx_check(const rdbx_t *rdbx, int difference); | |
140 | 126 |
141 /* | 127 /* |
142 * replay_add_index(rdbx, delta) | 128 * srtp_replay_add_index(rdbx, delta) |
143 * | 129 * |
144 * adds the xtd_seq_num_t at rdbx->window_start + delta to replay_db | 130 * adds the srtp_xtd_seq_num_t at rdbx->window_start + delta to replay_db |
145 * (and does *not* check if that xtd_seq_num_t appears in db) | 131 * (and does *not* check if that xtd_seq_num_t appears in db) |
146 * | 132 * |
147 * this function should be called *only* after replay_check has | 133 * this function should be called *only* after replay_check has |
148 * indicated that the index does not appear in the rdbx, and a mutex | 134 * indicated that the index does not appear in the rdbx, and a mutex |
149 * should protect the rdbx between these calls if necessary. | 135 * should protect the rdbx between these calls if necessary. |
150 */ | 136 */ |
151 | 137 srtp_err_status_t srtp_rdbx_add_index(srtp_rdbx_t *rdbx, int delta); |
152 err_status_t | |
153 rdbx_add_index(rdbx_t *rdbx, int delta); | |
154 | 138 |
155 | 139 |
156 /* | 140 /* |
157 * rdbx_set_roc(rdbx, roc) initalizes the rdbx_t at the location rdbx | 141 * srtp_rdbx_set_roc(rdbx, roc) initalizes the srtp_rdbx_t at the location rdbx |
158 * to have the rollover counter value roc. If that value is less than | 142 * to have the rollover counter value roc. If that value is less than |
159 * the current rollover counter value, then the function returns | 143 * the current rollover counter value, then the function returns |
160 * err_status_replay_old; otherwise, err_status_ok is returned. | 144 * srtp_err_status_replay_old; otherwise, srtp_err_status_ok is returned. |
161 * | 145 * |
162 */ | 146 */ |
163 | 147 srtp_err_status_t srtp_rdbx_set_roc(srtp_rdbx_t *rdbx, uint32_t roc); |
164 err_status_t | |
165 rdbx_set_roc(rdbx_t *rdbx, uint32_t roc); | |
166 | 148 |
167 /* | 149 /* |
168 * rdbx_get_roc(rdbx) returns the value of the rollover counter for | 150 * srtp_rdbx_get_roc(rdbx) returns the value of the rollover counter for |
169 * the rdbx_t pointed to by rdbx | 151 * the srtp_rdbx_t pointed to by rdbx |
170 * | 152 * |
171 */ | 153 */ |
172 | 154 srtp_xtd_seq_num_t srtp_rdbx_get_packet_index(const srtp_rdbx_t *rdbx); |
173 xtd_seq_num_t | |
174 rdbx_get_packet_index(const rdbx_t *rdbx); | |
175 | 155 |
176 /* | 156 /* |
177 * xtd_seq_num_t functions - these are *internal* functions of rdbx, and | 157 * srtp_xtd_seq_num_t functions - these are *internal* functions of rdbx, and |
178 * shouldn't be used to manipulate rdbx internal values. use the rdbx | 158 * shouldn't be used to manipulate rdbx internal values. use the rdbx |
179 * api instead! | 159 * api instead! |
180 */ | 160 */ |
181 | 161 |
182 /* | 162 /* |
183 * rdbx_get_ws(rdbx_ptr) | 163 * srtp_rdbx_get_ws(rdbx_ptr) |
184 * | 164 * |
185 * gets the window size which was used to initialize the rdbx | 165 * gets the window size which was used to initialize the rdbx |
186 */ | 166 */ |
187 | 167 unsigned long srtp_rdbx_get_window_size(const srtp_rdbx_t *rdbx); |
188 unsigned long | |
189 rdbx_get_window_size(const rdbx_t *rdbx); | |
190 | 168 |
191 | 169 |
192 /* index_init(&pi) initializes a packet index pi (sets it to zero) */ | 170 /* index_init(&pi) initializes a packet index pi (sets it to zero) */ |
193 | 171 void srtp_index_init(srtp_xtd_seq_num_t *pi); |
194 void | |
195 index_init(xtd_seq_num_t *pi); | |
196 | 172 |
197 /* index_advance(&pi, s) advances a xtd_seq_num_t forward by s */ | 173 /* index_advance(&pi, s) advances a xtd_seq_num_t forward by s */ |
198 | 174 void srtp_index_advance(srtp_xtd_seq_num_t *pi, srtp_sequence_number_t s); |
199 void | |
200 index_advance(xtd_seq_num_t *pi, sequence_number_t s); | |
201 | 175 |
202 | 176 |
203 /* | 177 /* |
204 * index_guess(local, guess, s) | 178 * srtp_index_guess(local, guess, s) |
205 * | 179 * |
206 * given a xtd_seq_num_t local (which represents the highest | 180 * given a srtp_xtd_seq_num_t local (which represents the highest |
207 * known-to-be-good index) and a sequence number s (from a newly | 181 * known-to-be-good index) and a sequence number s (from a newly |
208 * arrived packet), sets the contents of *guess to contain the best | 182 * arrived packet), sets the contents of *guess to contain the best |
209 * guess of the packet index to which s corresponds, and returns the | 183 * guess of the packet index to which s corresponds, and returns the |
210 * difference between *guess and *local | 184 * difference between *guess and *local |
211 */ | 185 */ |
212 | 186 int srtp_index_guess(const srtp_xtd_seq_num_t *local, srtp_xtd_seq_num_t *guess,
srtp_sequence_number_t s); |
213 int | |
214 index_guess(const xtd_seq_num_t *local, | |
215 » » xtd_seq_num_t *guess, | |
216 » » sequence_number_t s); | |
217 | 187 |
218 | 188 |
| 189 #ifdef __cplusplus |
| 190 } |
| 191 #endif |
| 192 |
219 #endif /* RDBX_H */ | 193 #endif /* RDBX_H */ |
220 | |
221 | |
222 | |
223 | |
224 | |
225 | |
226 | |
227 | |
228 | |
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