1 // SPDX-License-Identifier: BSD-2-Clause
2 /*
3 * Copyright (C) 2023 The Android Open Source Project
4 */
5
6 #include <common.h>
7 #include <fastboot.h>
8 #include <net.h>
9 #include <net/fastboot_tcp.h>
10 #include <net/tcp.h>
11
12 static char command[FASTBOOT_COMMAND_LEN] = {0};
13 static char response[FASTBOOT_RESPONSE_LEN] = {0};
14
15 static const unsigned short handshake_length = 4;
16 static const uchar *handshake = "FB01";
17
18 static u16 curr_sport;
19 static u16 curr_dport;
20 static u32 curr_tcp_seq_num;
21 static u32 curr_tcp_ack_num;
22 static unsigned int curr_request_len;
23 static enum fastboot_tcp_state {
24 FASTBOOT_CLOSED,
25 FASTBOOT_CONNECTED,
26 FASTBOOT_DISCONNECTING
27 } state = FASTBOOT_CLOSED;
28
fastboot_tcp_answer(u8 action,unsigned int len)29 static void fastboot_tcp_answer(u8 action, unsigned int len)
30 {
31 const u32 response_seq_num = curr_tcp_ack_num;
32 const u32 response_ack_num = curr_tcp_seq_num +
33 (curr_request_len > 0 ? curr_request_len : 1);
34
35 net_send_tcp_packet(len, htons(curr_sport), htons(curr_dport),
36 action, response_seq_num, response_ack_num);
37 }
38
fastboot_tcp_reset(void)39 static void fastboot_tcp_reset(void)
40 {
41 fastboot_tcp_answer(TCP_RST, 0);
42 state = FASTBOOT_CLOSED;
43 }
44
fastboot_tcp_send_packet(u8 action,const uchar * data,unsigned int len)45 static void fastboot_tcp_send_packet(u8 action, const uchar *data, unsigned int len)
46 {
47 uchar *pkt = net_get_async_tx_pkt_buf();
48
49 memset(pkt, '\0', PKTSIZE);
50 pkt += net_eth_hdr_size() + IP_TCP_HDR_SIZE + TCP_TSOPT_SIZE + 2;
51 memcpy(pkt, data, len);
52 fastboot_tcp_answer(action, len);
53 memset(pkt, '\0', PKTSIZE);
54 }
55
fastboot_tcp_send_message(const char * message,unsigned int len)56 static void fastboot_tcp_send_message(const char *message, unsigned int len)
57 {
58 __be64 len_be = __cpu_to_be64(len);
59 uchar *pkt = net_get_async_tx_pkt_buf();
60
61 memset(pkt, '\0', PKTSIZE);
62 pkt += net_eth_hdr_size() + IP_TCP_HDR_SIZE + TCP_TSOPT_SIZE + 2;
63 // Put first 8 bytes as a big endian message length
64 memcpy(pkt, &len_be, 8);
65 pkt += 8;
66 memcpy(pkt, message, len);
67 fastboot_tcp_answer(TCP_ACK | TCP_PUSH, len + 8);
68 memset(pkt, '\0', PKTSIZE);
69 }
70
fastboot_tcp_handler_ipv4(uchar * pkt,u16 dport,struct in_addr sip,u16 sport,u32 tcp_seq_num,u32 tcp_ack_num,u8 action,unsigned int len)71 static void fastboot_tcp_handler_ipv4(uchar *pkt, u16 dport,
72 struct in_addr sip, u16 sport,
73 u32 tcp_seq_num, u32 tcp_ack_num,
74 u8 action, unsigned int len)
75 {
76 int fastboot_command_id;
77 u64 command_size;
78 u8 tcp_fin = action & TCP_FIN;
79 u8 tcp_push = action & TCP_PUSH;
80
81 curr_sport = sport;
82 curr_dport = dport;
83 curr_tcp_seq_num = tcp_seq_num;
84 curr_tcp_ack_num = tcp_ack_num;
85 curr_request_len = len;
86
87 switch (state) {
88 case FASTBOOT_CLOSED:
89 if (tcp_push) {
90 if (len != handshake_length ||
91 strlen(pkt) != handshake_length ||
92 memcmp(pkt, handshake, handshake_length) != 0) {
93 fastboot_tcp_reset();
94 break;
95 }
96 fastboot_tcp_send_packet(TCP_ACK | TCP_PUSH,
97 handshake, handshake_length);
98 state = FASTBOOT_CONNECTED;
99 }
100 break;
101 case FASTBOOT_CONNECTED:
102 if (tcp_fin) {
103 fastboot_tcp_answer(TCP_FIN | TCP_ACK, 0);
104 state = FASTBOOT_DISCONNECTING;
105 break;
106 }
107 if (tcp_push) {
108 // First 8 bytes is big endian message length
109 command_size = __be64_to_cpu(*(u64 *)pkt);
110 len -= 8;
111 pkt += 8;
112
113 // Only single packet messages are supported ATM
114 if (strlen(pkt) != command_size) {
115 fastboot_tcp_reset();
116 break;
117 }
118 strlcpy(command, pkt, len + 1);
119 fastboot_command_id = fastboot_handle_command(command, response);
120 fastboot_tcp_send_message(response, strlen(response));
121 fastboot_handle_boot(fastboot_command_id,
122 strncmp("OKAY", response, 4) == 0);
123 }
124 break;
125 case FASTBOOT_DISCONNECTING:
126 if (tcp_push)
127 state = FASTBOOT_CLOSED;
128 break;
129 }
130
131 memset(command, 0, FASTBOOT_COMMAND_LEN);
132 memset(response, 0, FASTBOOT_RESPONSE_LEN);
133 curr_sport = 0;
134 curr_dport = 0;
135 curr_tcp_seq_num = 0;
136 curr_tcp_ack_num = 0;
137 curr_request_len = 0;
138 }
139
fastboot_tcp_start_server(void)140 void fastboot_tcp_start_server(void)
141 {
142 printf("Using %s device\n", eth_get_name());
143 printf("Listening for fastboot command on tcp %pI4\n", &net_ip);
144
145 tcp_set_tcp_handler(fastboot_tcp_handler_ipv4);
146 }
147