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client: Change wire format!: Add epoch
[tattlekey] / client / net.c
1 /* tattlekey: A one-key UDP keyboard
2 * Copyright (C) 2023 Scott Worley <scottworley@scottworley.com>
3 *
4 * This program is free software: you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation, either version 3 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program. If not, see <https://www.gnu.org/licenses/>.
16 */
17
18 #include "net.h"
19 #include "blink.h"
20 #include "config.h"
21
22 #include "pico/cyw43_arch.h"
23 #include "pico/rand.h"
24
25 #include "lwip/pbuf.h"
26 #include "lwip/udp.h"
27
28 /* We only ever send to one address, and we only ever have one thread, so just
29 * use one udp_pcb */
30 static struct udp_pcb *the_pcb = NULL;
31 static uint32_t epoch = 0;
32
33 static void net_local_init() {
34 if (the_pcb)
35 return;
36
37 epoch = get_rand_32();
38
39 the_pcb = udp_new();
40 if (!the_pcb)
41 signal_error_by_blinking();
42
43 ip_addr_t ipaddr;
44 if (ip4addr_aton(config_tattle_server_ip_address, &ipaddr) == 0)
45 signal_error_by_blinking();
46
47 if (udp_connect(the_pcb, &ipaddr, config_tattle_port) != ERR_OK)
48 signal_error_by_blinking();
49 }
50
51 struct tattle_message_wire_format {
52 u32_t epoch;
53 u16_t sender;
54 u16_t seq;
55 u32_t ago;
56 };
57
58 void send_report_packet(u16_t seq, u32_t ago) {
59 cyw43_arch_lwip_begin();
60
61 net_local_init();
62
63 struct pbuf *p = pbuf_alloc(
64 PBUF_TRANSPORT, sizeof(struct tattle_message_wire_format), PBUF_RAM);
65 if (!p)
66 signal_error_by_blinking();
67
68 struct tattle_message_wire_format *msg =
69 (struct tattle_message_wire_format *)(p->payload);
70 msg->epoch = htonl(epoch);
71 msg->sender = htons(config_this_tattler_identity);
72 msg->seq = htons(seq);
73 msg->ago = htonl(ago);
74
75 if (udp_send(the_pcb, p) != ERR_OK)
76 signal_error_by_blinking();
77
78 pbuf_free(p);
79
80 cyw43_arch_lwip_end();
81 }