2  * Copyright 2023-2025 The OpenSSL Project Authors. All Rights Reserved.
59             data->backoff = (int)num;  in noisy_dgram_ctrl()
69             data->noise_rate = (int)num;  in noisy_dgram_ctrl()
79             data->recv_limit.bw = (size_t)num;  in noisy_dgram_ctrl()
89             data->send_limit.bw = (size_t)num;  in noisy_dgram_ctrl()
100             data->now_cb = now_cb->now_cb;  in noisy_dgram_ctrl()
101             data->now_cb_arg = now_cb->now_cb_arg;  in noisy_dgram_ctrl()
119     if (limit->bw == 0) /* 0 -> no limit */  in bandwidth_limit()
126     for (i = 0; i < limit->num; i++) {  in bandwidth_limit()
127         size_t idx = (limit->start + i) % MAX_PKTS_PER_WINDOW;  in bandwidth_limit()
129         if (ossl_time_compare(limit->pinfos[idx].timestamp, sampling_start) >= 0)  in bandwidth_limit()
131         limit->size_sum -= limit->pinfos[idx].size;  in bandwidth_limit()
133     limit->start = (limit->start + i) % MAX_PKTS_PER_WINDOW;  in bandwidth_limit()
134     limit->num -= i;  in bandwidth_limit()
140          if ((limit->size_sum + pktsize) / SAMPLING_WINDOW_PERIOD > limit->bw) {  in bandwidth_limit()
155          if (limit->num >= MAX_PKTS_PER_WINDOW) {  in bandwidth_limit()
156              limit->size_sum -= limit->pinfos[limit->start].size;  in bandwidth_limit()
157              limit->start = (limit->start + 1) % MAX_PKTS_PER_WINDOW;  in bandwidth_limit()
159            ++limit->num;  in bandwidth_limit()
161          end = (limit->start + limit->num) % MAX_PKTS_PER_WINDOW;  in bandwidth_limit()
162          limit->pinfos[end].size = pktsize;  in bandwidth_limit()
163          limit->pinfos[end].timestamp = now;  in bandwidth_limit()
164          limit->size_sum += pktsize;  in bandwidth_limit()
184     now = data->now_cb != NULL ? data->now_cb(data->now_cb_arg)  in noisy_dgram_sendmmsg()
188     num_msg = bandwidth_limit(&data->send_limit, now, msg, num_msg);  in noisy_dgram_sendmmsg()
196      * We only introduce noise when receiving messages. We just pass this on  in noisy_dgram_sendmmsg()
206  * We have 3 different types of noise: drop, duplicate and delay
216  * When a duplicate occurs we reinject the new datagram after up to
221  * This also controls when a delay (not a duplicate) occurs. In that case
222  * we add 1 to the number because there is no point in skipping the current
243      * Of noisy datagrams, 25% drop, 25% duplicate, 25% delay, 25% flip bits  in get_noise()
253      * Where a duplicate occurs we reinject the copy of the datagram up to  in get_noise()
262      * dropped (i.e. this is a delay not a duplicate), so we reinject after an  in get_noise()
263      * extra datagram in that case  in get_noise()
269         /* we flip at most 8 bits of the 16 bit value at once */  in get_noise()
289         flip_offset = msg_len - 2;  in flip_bits()
320      * For simplicity we assume that all elements in the msg array have the  in noisy_dgram_recvmmsg()
322      * strange for that not to be the case - and our code that calls  in noisy_dgram_recvmmsg()
324      * code). We test the invariant here.  in noisy_dgram_recvmmsg()
340     printf("Pre-filter datagram list:\n");  in noisy_dgram_recvmmsg()
342         printf("Pre-filter Datagram:\n");  in noisy_dgram_recvmmsg()
346     printf("End of pre-filter datagram list\nApplying noise filters:\n");  in noisy_dgram_recvmmsg()
349     now = data->now_cb != NULL ? data->now_cb(data->now_cb_arg)  in noisy_dgram_recvmmsg()
353     msg_cnt = bandwidth_limit(&data->recv_limit, now, msg, msg_cnt);  in noisy_dgram_recvmmsg()
357     if (data->noise_rate == 0)  in noisy_dgram_recvmmsg()
363          i++, thismsg++, data->this_dgram++) {  in noisy_dgram_recvmmsg()
369         /* If we have a message to reinject then insert it now */  in noisy_dgram_recvmmsg()
370         if (data->reinject_dgram > 0  in noisy_dgram_recvmmsg()
371                 && data->reinject_dgram == data->this_dgram) {  in noisy_dgram_recvmmsg()
374                 for (j = msg_cnt; j > i; j--) {  in noisy_dgram_recvmmsg()
375                     if (!bio_msg_copy(&msg[j], &msg[j - 1]))  in noisy_dgram_recvmmsg()
378                 if (!bio_msg_copy(thismsg, &data->msg))  in noisy_dgram_recvmmsg()
381                 data->reinject_dgram = 0;  in noisy_dgram_recvmmsg()
384                 BIO_dump_fp(stdout, thismsg->data, thismsg->data_len);  in noisy_dgram_recvmmsg()
388             } /* else we have no space for the injection, so just drop it */  in noisy_dgram_recvmmsg()
389             data->reinject_dgram = 0;  in noisy_dgram_recvmmsg()
392         get_noise(data->noise_rate,  in noisy_dgram_recvmmsg()
393                   /* long header */ (((uint8_t *)thismsg->data)[0] & 0x80) != 0,  in noisy_dgram_recvmmsg()
395         if (data->backoff) {  in noisy_dgram_recvmmsg()
397              * We might be asked to back off on introducing too much noise if  in noisy_dgram_recvmmsg()
399              * we always ensure that the next datagram does not get dropped so  in noisy_dgram_recvmmsg()
400              * that the connection always survives. After that we can resume  in noisy_dgram_recvmmsg()
410             data->backoff--;  in noisy_dgram_recvmmsg()
413         flip_bits(thismsg->data, thismsg->data_len, flip, flip_offset);  in noisy_dgram_recvmmsg()
416          * We ignore reinjection if a message is already waiting to be  in noisy_dgram_recvmmsg()
419         if (reinject > 0 && data->reinject_dgram == 0) {  in noisy_dgram_recvmmsg()
422              * delay period. Datagrams that are delayed only (not duplicated)  in noisy_dgram_recvmmsg()
426             if (!bio_msg_copy(&data->msg, thismsg))  in noisy_dgram_recvmmsg()
429             data->reinject_dgram = data->this_dgram + reinject;  in noisy_dgram_recvmmsg()
434             BIO_dump_fp(stdout, thismsg->data, thismsg->data_len);  in noisy_dgram_recvmmsg()
442             BIO_dump_fp(stdout, thismsg->data, thismsg->data_len);  in noisy_dgram_recvmmsg()
446                 if (!bio_msg_copy(&msg[j - 1], &msg[j]))  in noisy_dgram_recvmmsg()
449             msg_cnt--;  in noisy_dgram_recvmmsg()
454     printf("End of noise filters\nPost-filter datagram list:\n");  in noisy_dgram_recvmmsg()
456         printf("Post-filter Datagram:\n");  in noisy_dgram_recvmmsg()
460     printf("End of post-filter datagram list\n");  in noisy_dgram_recvmmsg()
479     OPENSSL_free(data->msg.data);  in data_free()
480     BIO_ADDR_free(data->msg.peer);  in data_free()
481     BIO_ADDR_free(data->msg.local);  in data_free()
492     data->noise_rate = NOISE_RATE;  in noisy_dgram_new()
493     data->msg.data = OPENSSL_malloc(MSG_DATA_LEN_MAX);  in noisy_dgram_new()
494     data->msg.peer = BIO_ADDR_new();  in noisy_dgram_new()
495     data->msg.local = BIO_ADDR_new();  in noisy_dgram_new()
496     if (data->msg.data == NULL  in noisy_dgram_new()
497             || data->msg.peer == NULL  in noisy_dgram_new()
498             || data->msg.local == NULL) {  in noisy_dgram_new()