1 | //////////////////////////////////////////////////////////////////////////////// |
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2 | // Copyright (c) 2004 Xilinx, Inc. All rights reserved. |
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3 | // |
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4 | // Xilinx, Inc. |
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5 | // XILINX IS PROVIDING THIS DESIGN, CODE, OR INFORMATION "AS IS" AS A |
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6 | // COURTESY TO YOU. BY PROVIDING THIS DESIGN, CODE, OR INFORMATION AS |
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7 | // ONE POSSIBLE IMPLEMENTATION OF THIS FEATURE, APPLICATION OR |
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8 | // STANDARD, XILINX IS MAKING NO REPRESENTATION THAT THIS IMPLEMENTATION |
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9 | // IS FREE FROM ANY CLAIMS OF INFRINGEMENT, AND YOU ARE RESPONSIBLE |
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10 | // FOR OBTAINING ANY RIGHTS YOU MAY REQUIRE FOR YOUR IMPLEMENTATION. |
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11 | // XILINX EXPRESSLY DISCLAIMS ANY WARRANTY WHATSOEVER WITH RESPECT TO |
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12 | // THE ADEQUACY OF THE IMPLEMENTATION, INCLUDING BUT NOT LIMITED TO |
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13 | // ANY WARRANTIES OR REPRESENTATIONS THAT THIS IMPLEMENTATION IS FREE |
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14 | // FROM CLAIMS OF INFRINGEMENT, IMPLIED WARRANTIES OF MERCHANTABILITY |
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15 | // AND FITNESS FOR A PARTICULAR PURPOSE. |
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16 | // |
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17 | // File : tcp.c |
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18 | // Date : 2002, March 20. |
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19 | // Author : Sathya Thammanur |
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20 | // Company: Xilinx |
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21 | // Group : Emerging Software Technologies |
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22 | // |
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23 | // Summary: |
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24 | // TCP layer specific functions |
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25 | // |
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26 | // $Id: tcp.c,v 1.2.8.6 2005/11/15 23:41:10 salindac Exp $ |
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27 | // |
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28 | //////////////////////////////////////////////////////////////////////////////// |
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29 | |
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30 | //////////////////////////////////////////////////////////////////////////////// |
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31 | // see copyright.txt for Rice University/Mango Communications modifications |
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32 | //////////////////////////////////////////////////////////////////////////////// |
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33 | |
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34 | #include <xilnet_xilsock.h> |
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35 | |
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36 | #ifndef NULL |
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37 | #define NULL 0 |
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38 | #endif |
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39 | |
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40 | struct xilnet_tcp_conn xilnet_tcp_conns[MAX_TCP_CONNS]; |
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41 | |
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42 | /* |
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43 | * tcp packet handler: |
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44 | * "buf" is a IP datagram |
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45 | * tcp identifies the right connection the pkt is destined for |
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46 | * returns "0", if pkt for existing conn |
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47 | * returns "-1", if incorrect pkt |
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48 | * returns XILSOCK_NEW_CONN for a new conn |
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49 | */ |
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50 | |
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51 | int xilnet_tcp(unsigned char* buf, int len) { |
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52 | |
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53 | struct xilnet_tcp_conn *curr_conn = NULL; |
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54 | struct xilnet_tcp_hdr tcp_req; |
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55 | unsigned char* tcp_reply = (sendbuf+LINK_HDR_LEN+(IP_HDR_LEN*4)); |
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56 | int tcpdata_in = 0; |
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57 | int listen_conn_index = -1; |
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58 | int reset = FALSE; |
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59 | int i; |
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60 | int iplen = 0; |
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61 | |
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62 | // set the tcp_req to zero |
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63 | memset((unsigned char*)&tcp_req, 0, sizeof(struct xilnet_tcp_hdr)); |
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64 | |
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65 | // cpy buf to tcp_req |
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66 | memcpy((unsigned char*)(&tcp_req), (buf+IP_HDR_LEN*4), (TCP_HDR_LEN*4)); |
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67 | |
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68 | // check for active conns |
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69 | for (i = 0; i < MAX_TCP_CONNS; i++) { |
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70 | if (xilnet_tcp_conns[i].state != TCP_CLOSED) { |
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71 | if ( (xilnet_tcp_conns[i].src_port == tcp_req.dst_port)) { |
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72 | if ( (xilnet_tcp_conns[i].dst_port == tcp_req.src_port) && |
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73 | (xilnet_tcp_conns[i].dst_ip[0] == buf[IP_SADDR_BASE]) && |
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74 | (xilnet_tcp_conns[i].dst_ip[1] == buf[IP_SADDR_BASE+1]) && |
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75 | (xilnet_tcp_conns[i].dst_ip[2] == buf[IP_SADDR_BASE+2]) && |
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76 | (xilnet_tcp_conns[i].dst_ip[3] == buf[IP_SADDR_BASE+3]) |
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77 | ) { |
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78 | curr_conn = &(xilnet_tcp_conns[i]); |
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79 | break; |
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80 | } |
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81 | else { |
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82 | listen_conn_index = i; |
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83 | } |
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84 | } |
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85 | } |
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86 | } |
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87 | |
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88 | // no activeconn found. check for listening conn |
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89 | if (!curr_conn) { |
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90 | if (listen_conn_index < 0) { |
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91 | reset = TRUE; |
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92 | } |
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93 | else { |
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94 | if (tcp_req.syn) { |
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95 | curr_conn = &(xilnet_tcp_conns[listen_conn_index]); |
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96 | curr_conn->dst_port = tcp_req.src_port; |
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97 | curr_conn->dst_ip[0] = buf[IP_SADDR_BASE] ; |
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98 | curr_conn->dst_ip[1] = buf[IP_SADDR_BASE+1]; |
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99 | curr_conn->dst_ip[2] = buf[IP_SADDR_BASE+2] ; |
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100 | curr_conn->dst_ip[3] = buf[IP_SADDR_BASE+3]; |
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101 | } |
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102 | else |
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103 | reset = TRUE; |
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104 | } |
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105 | } |
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106 | |
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107 | // check if reset flag is set and send a reset packet |
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108 | if (reset) { |
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109 | struct xilnet_tcp_conn conn = {0}; |
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110 | conn.src_port = tcp_req.dst_port; |
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111 | conn.dst_port = tcp_req.src_port; |
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112 | conn.seqno = tcp_req.ack_no; |
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113 | conn.ack_seqno = tcp_req.seq_no; |
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114 | conn.dst_ip[0] = buf[IP_SADDR_BASE]; |
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115 | conn.dst_ip[1] = buf[IP_SADDR_BASE+1]; |
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116 | conn.dst_ip[2] = buf[IP_SADDR_BASE+2] ; |
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117 | conn.dst_ip[3] = buf[IP_SADDR_BASE+3]; |
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118 | memset(sendbuf, 0, LINK_FRAME_LEN); |
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119 | xilnet_tcp_send_pkt(&conn, sendbuf+LINK_HDR_LEN+IP_HDR_LEN*4, 0, TCP_RST); |
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120 | xilnet_ip_header(sendbuf+LINK_HDR_LEN, (TCP_HDR_LEN*4)+IP_HDR_LEN*4, IP_PROTO_TCP, conn.dst_ip); |
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121 | xilnet_eth_send_frame(sendbuf, (TCP_HDR_LEN*4)+IP_HDR_LEN*4+ETH_HDR_LEN, conn.dst_ip, NULL, ETH_PROTO_IP); |
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122 | return 0; |
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123 | } |
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124 | |
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125 | tcpdata_in = len - (IP_HDR_LEN*4) - (tcp_req.hdr_len*4); |
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126 | |
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127 | // check for corr acknum if not a syn packet |
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128 | if ( (!tcp_req.syn) && (tcp_req.ack_no != curr_conn->exp_acknum)) { |
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129 | print("tcp: incorrect acknum \n"); |
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130 | return -1; |
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131 | } |
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132 | |
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133 | switch (curr_conn->state) { |
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134 | |
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135 | case TCP_LISTEN: |
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136 | // incoming SYN;send ACK and Seqno |
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137 | if (tcp_req.syn) { |
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138 | unsigned char flags = 0; |
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139 | unsigned short check = 0; |
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140 | |
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141 | // set ack_seqno |
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142 | curr_conn->ack_seqno = tcp_req.seq_no + 1; |
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143 | curr_conn->state = TCP_SYN_RCVD; |
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144 | xilsock_sockets[curr_conn->fd].recvbuf.buf = buf; |
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145 | xilsock_sockets[curr_conn->fd].recvbuf.size = tcpdata_in; |
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146 | return XILSOCK_NEW_CONN; |
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147 | } |
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148 | return -1; |
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149 | break; |
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150 | |
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151 | case TCP_SYN_RCVD: |
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152 | // incoming ACK & no data; |
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153 | if (tcp_req.ack && (!tcpdata_in)) { |
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154 | // set the ack_seq |
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155 | curr_conn->ack_seqno = tcp_req.seq_no + 1; |
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156 | curr_conn->seqno = tcp_req.ack_no; |
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157 | curr_conn->state = TCP_ESTABLISHED; |
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158 | xilsock_sockets[curr_conn->fd].recvbuf.buf = buf; |
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159 | xilsock_sockets[curr_conn->fd].recvbuf.size = tcpdata_in; |
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160 | return XILSOCK_SYNACK_RCVD; |
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161 | } |
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162 | return -1; |
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163 | break; |
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164 | |
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165 | case TCP_ESTABLISHED: |
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166 | // incoming ACK; data in; |
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167 | if (tcp_req.ack && (tcpdata_in)) { |
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168 | // set the ack seq |
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169 | curr_conn->ack_seqno = tcp_req.seq_no + tcpdata_in; |
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170 | curr_conn->seqno = tcp_req.ack_no; |
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171 | |
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172 | // strip tcp header |
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173 | buf = buf + (IP_HDR_LEN*4) +(TCP_HDR_LEN*4); |
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174 | |
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175 | // update socket corr to this conn |
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176 | xilsock_sockets[curr_conn->fd].recvbuf.buf = buf; |
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177 | xilsock_sockets[curr_conn->fd].recvbuf.size = tcpdata_in; |
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178 | return XILSOCK_TCP_DATA; |
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179 | } |
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180 | else if (tcp_req.ack && (!tcpdata_in)) { |
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181 | // set the ack seq |
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182 | curr_conn->ack_seqno = tcp_req.seq_no + 1; |
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183 | curr_conn->seqno = tcp_req.ack_no; |
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184 | xilsock_sockets[curr_conn->fd].recvbuf.buf = buf; |
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185 | xilsock_sockets[curr_conn->fd].recvbuf.size = tcpdata_in; |
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186 | return XILSOCK_TCP_ACK; |
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187 | } |
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188 | return -1; |
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189 | break; |
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190 | |
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191 | case TCP_FIN_WAIT1: |
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192 | // wait for fin ack |
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193 | if (tcp_req.ack && (!tcpdata_in)) { |
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194 | curr_conn->ack_seqno = tcp_req.seq_no + 1; |
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195 | curr_conn->seqno = tcp_req.ack_no; |
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196 | |
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197 | if (tcp_req.fin) { |
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198 | |
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199 | // send ack for FIN |
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200 | memset(sendbuf, 0, LINK_FRAME_LEN); |
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201 | xilnet_tcp_send_pkt(curr_conn, sendbuf+LINK_HDR_LEN+IP_HDR_LEN*4, 0, TCP_ACK); |
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202 | xilnet_ip_header(sendbuf+LINK_HDR_LEN, (TCP_HDR_LEN*4)+IP_HDR_LEN*4, IP_PROTO_TCP, curr_conn->dst_ip); |
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203 | xilnet_eth_send_frame(sendbuf, (TCP_HDR_LEN*4)+IP_HDR_LEN*4+ETH_HDR_LEN, curr_conn->dst_ip, NULL, ETH_PROTO_IP); |
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204 | |
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205 | // reset tcp conn state |
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206 | xilsock_sockets[curr_conn->fd].closed = 1; |
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207 | return XILSOCK_CLOSE_CONN; |
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208 | } |
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209 | curr_conn->state = TCP_FIN_WAIT2; |
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210 | xilsock_sockets[curr_conn->fd].recvbuf.buf = buf; |
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211 | xilsock_sockets[curr_conn->fd].recvbuf.size = tcpdata_in; |
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212 | } |
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213 | return -1; |
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214 | break; |
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215 | |
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216 | case TCP_FIN_WAIT2: |
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217 | // incoming FIN; |
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218 | if (tcp_req.fin) { |
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219 | // set the ack seq |
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220 | curr_conn->ack_seqno = tcp_req.seq_no + 1; |
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221 | curr_conn->seqno = tcp_req.ack_no; |
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222 | |
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223 | // send ack for FIN |
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224 | memset(sendbuf, 0, LINK_FRAME_LEN); |
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225 | xilnet_tcp_send_pkt(curr_conn, sendbuf+LINK_HDR_LEN+IP_HDR_LEN*4, 0, TCP_ACK); |
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226 | xilnet_ip_header(sendbuf+LINK_HDR_LEN, (TCP_HDR_LEN*4)+IP_HDR_LEN*4, IP_PROTO_TCP, curr_conn->dst_ip); |
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227 | xilnet_eth_send_frame(sendbuf, (TCP_HDR_LEN*4)+IP_HDR_LEN*4+ETH_HDR_LEN, curr_conn->dst_ip, NULL, ETH_PROTO_IP); |
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228 | |
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229 | // reset tcp conn state |
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230 | xilsock_sockets[curr_conn->fd].closed = 1; |
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231 | return XILSOCK_CLOSE_CONN; |
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232 | } |
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233 | break; |
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234 | default: |
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235 | return 0; |
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236 | break; |
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237 | } |
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238 | } |
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239 | |
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240 | |
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241 | /* |
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242 | * xilnet_tcp_send_pkt: sends a tcp packet from "conn", with flags |
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243 | */ |
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244 | |
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245 | void xilnet_tcp_send_pkt(struct xilnet_tcp_conn *conn, unsigned char* buf, int len, unsigned char flags) { |
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246 | |
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247 | unsigned short check = 0; |
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248 | |
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249 | |
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250 | // call tcp_header |
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251 | xilnet_tcp_header(conn, buf, len, flags); |
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252 | |
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253 | // calculate checksum |
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254 | check = xilnet_udp_tcp_calc_chksum(buf, len+(TCP_HDR_LEN*4), node_ip_addr, conn->dst_ip, IP_PROTO_TCP); |
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255 | buf[TCP_CHECK_OFF] = (check & 0xff00) >> 8; |
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256 | buf[TCP_CHECK_OFF+1] = (check & 0x00ff); |
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257 | |
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258 | } |
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259 | |
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260 | |
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261 | /* |
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262 | * xilnet_tcp_header: creates tcp header |
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263 | */ |
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264 | void xilnet_tcp_header(struct xilnet_tcp_conn *conn, unsigned char* buf, int len, unsigned char flags) { |
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265 | |
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266 | struct xilnet_tcp_hdr tcph; |
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267 | |
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268 | memset((unsigned char*) &tcph, 0, sizeof(struct xilnet_tcp_hdr)); |
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269 | if (conn) { |
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270 | tcph.src_port = conn->src_port; |
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271 | tcph.dst_port = conn->dst_port; |
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272 | tcph.seq_no = conn->seqno; |
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273 | conn->exp_acknum = conn->seqno + len; |
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274 | tcph.ack_no = conn->ack_seqno; |
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275 | } |
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276 | |
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277 | tcph.hdr_len = TCP_HDR_LEN; |
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278 | tcph.reserved = 0; |
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279 | tcph.urg = (flags & TCP_URG) ? 1:0; |
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280 | tcph.ack = (flags & TCP_ACK) ? 1:0; |
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281 | tcph.psh = (flags & TCP_PSH) ? 1:0; |
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282 | tcph.rst = (flags & TCP_RST) ? 1:0; |
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283 | tcph.syn = (flags & TCP_SYN) ? 1:0; |
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284 | if (flags & TCP_FIN) { |
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285 | tcph.fin = 1; |
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286 | tcph.ack_no -= 1; |
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287 | } |
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288 | |
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289 | tcph.window_size[0] = TCP_WND_HIGH; |
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290 | tcph.window_size[1] = TCP_WND_LOW; |
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291 | tcph.check_sum = 0; |
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292 | tcph.urg_ptr = 0; |
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293 | |
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294 | memcpy(buf, (unsigned char *) &tcph, (TCP_HDR_LEN*4)); |
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295 | } |
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296 | |
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297 | |
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298 | /***************************** |
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299 | * tcp connection management * |
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300 | *****************************/ |
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301 | |
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302 | /* |
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303 | * initialise all tcp conns |
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304 | */ |
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305 | |
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306 | #define XILNET_TCP_SYS_PORT 8000 |
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307 | unsigned char istcpinit = 0; |
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308 | void xilnet_tcp_init_conns() { |
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309 | |
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310 | int i; |
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311 | |
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312 | for (i = 0; i < MAX_TCP_CONNS; i++) { |
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313 | xilnet_tcp_conns[i].state = TCP_CLOSED; |
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314 | } |
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315 | } |
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316 | |
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317 | |
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318 | /* |
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319 | * open a tcp conn: |
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320 | * opens a new tcp conn and changes state to LISTEN |
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321 | * returns connection index if able to open else -1 if not possible |
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322 | */ |
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323 | |
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324 | int xilnet_tcp_open_conn(unsigned short port) { |
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325 | |
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326 | int i; |
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327 | |
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328 | if (!istcpinit) { |
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329 | xilnet_tcp_init_conns(); |
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330 | istcpinit = 1; |
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331 | } |
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332 | for (i = 0; i < MAX_TCP_CONNS; i++) { |
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333 | if (xilnet_tcp_conns[i].state == TCP_CLOSED) |
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334 | break; |
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335 | } |
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336 | |
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337 | if (i < MAX_TCP_CONNS) { |
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338 | xilnet_tcp_conns[i].src_port = port; |
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339 | xilnet_tcp_conns[i].state = TCP_LISTEN; |
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340 | xilnet_tcp_conns[i].seqno = 0; |
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341 | xilnet_tcp_conns[i].ack_seqno = 0; |
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342 | xilnet_tcp_conns[i].exp_acknum = 0; |
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343 | return i; |
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344 | } |
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345 | return -1; |
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346 | |
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347 | } |
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348 | |
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349 | |
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350 | /* close a tcp conn: |
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351 | * closes a tcp conn by changing state to TCP_CLOSED |
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352 | * returns 1 if able to close else return -1 |
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353 | */ |
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354 | |
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355 | int xilnet_tcp_close_conn(struct xilnet_tcp_conn *conn) { |
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356 | |
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357 | int i; |
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358 | |
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359 | for (i = 0; i < MAX_TCP_CONNS; i++) { |
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360 | if ((xilnet_tcp_conns+i) == conn) { |
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361 | xilnet_tcp_conns[i].state = TCP_CLOSED; |
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362 | return 1; |
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363 | } |
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364 | } |
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365 | return -1; |
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366 | } |
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