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N-sim
Emulation and simulation of Wireless Sensor Networks |
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/home/brennan/n-sim/OrbisQuartus/server/protocols/csmaca.c
Go to the documentation of this file.00001 00014 /* 00015 * Copyright 2007. Los Alamos National Security, LLC. This material 00016 * was produced under U.S. Government contract DE-AC52-06NA25396 for 00017 * Los Alamos National Laboratory (LANL), which is operated by Los 00018 * Alamos National Security, LLC, for the Department of Energy. The 00019 * U.S. Government has rights to use, reproduce, and distribute this 00020 * software. NEITHER THE GOVERNMENT NOR LOS ALAMOS NATIONAL SECURITY, 00021 * LLC, MAKES ANY WARRANTY, EXPRESS OR IMPLIED, OR ASSUMES ANY LEGAL 00022 * LIABILITY FOR THE USE OF THIS SOFTWARE. If software is modified to 00023 * produce derivative works, such modified software should be clearly 00024 * marked, so as not to confuse it with the version available from LANL. 00025 * 00026 * Additionally, this program is free software; you can redistribute 00027 * it and/or modify it under the terms of the GNU General Public 00028 * License as published by the Free Software Foundation; version 2 of 00029 * the License. Accordingly, this program is distributed in the hope 00030 * it will be useful, but WITHOUT ANY WARRANTY; without even the 00031 * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR 00032 * PURPOSE. See the GNU General Public License for more details. 00033 */ 00034 00035 00036 #include <string.h> 00037 #include <math.h> 00038 #include <stdlib.h> 00039 #include <stdio.h> 00040 #include <sys/time.h> 00041 #include "mac_lib.h" 00042 00043 #define OQ_OFDM 10 /* 802.11a (fake) */ 00044 00045 #define OQ_FHSS 50 00046 #define OQ_DSSS 20 /* 802.11b/g */ 00047 #define OQ_THRU 91 /* single char throughput in nanoseconds */ 00048 00049 00050 static volatile int rx_pending = 0; 00051 static volatile int tx_pending = 0; 00052 static volatile int available_slot = 0; 00053 static long sequence = 0; 00054 00055 static int csmaca_filter(struct oq_req_resp *rr, int oq_slot); 00056 long long csmaca_throughput(void); 00057 int csmaca_a_filter(struct oq_req_resp *rr); 00058 int csmaca_b_filter(struct oq_req_resp *rr); 00059 int csmaca_g_filter(struct oq_req_resp *rr); 00060 00061 00062 long long csmaca_throughput(void) 00063 { 00064 return (long long) OQ_THRU; 00065 } 00066 00067 00068 int csmaca_a_filter(struct oq_req_resp *rr) 00069 { 00070 return csmaca_filter(rr, OQ_OFDM); 00071 } 00072 00073 00074 int csmaca_b_filter(struct oq_req_resp *rr) 00075 { 00076 return csmaca_filter(rr, OQ_DSSS); 00077 } 00078 00079 00080 int csmaca_g_filter(struct oq_req_resp *rr) 00081 { 00082 return csmaca_filter(rr, OQ_DSSS); 00083 } 00084 00085 00086 static int csmaca_filter(struct oq_req_resp *rr, int oq_slot) 00087 { 00088 struct sock_buff msg; 00089 struct timeval seed; 00090 00091 if (rr == NULL) 00092 return -1; 00093 00094 msg = rr->msgs[0]; 00095 rr->num_msgs = 1; 00096 00097 msg.slot_time = oq_slot; 00098 gettimeofday(&seed, NULL); 00099 srand(seed.tv_sec + seed.tv_usec); 00100 00101 if (msg.tx_rx == OQ_RADIO_RX) { 00102 if (strncasecmp(msg.mac, "RTS", 3) == 0) { 00103 char *seqstr = strchr(msg.mac, ':') + 1; 00104 char *seqend = strchr(seqstr, ':'); 00105 char *lenstr = seqend + 1; 00106 char *lenend = strchr(lenstr, '|'); 00107 unsigned long long seq; 00108 unsigned int len; 00109 00110 seqend[0] = lenend[0] = '\0'; 00111 seq = strtoull(seqstr, NULL, 10); 00112 len = (int) strtoul(lenstr, NULL, 10); 00113 seqend[0] = ':'; 00114 lenend[0] = '|'; 00115 00116 if (!msg.to_me) 00117 available_slot = 2 + (int) 00118 ceil((len * csmaca_throughput()) / 00119 (double) msg.slot_time); 00120 msg.code = OQ_SKB_DROP; 00121 00122 if (msg.to_me && !rx_pending && !tx_pending) { 00123 struct sock_buff cts = rr->msgs[1]; 00124 rr->num_msgs = 2; 00125 cts.tx_rx = OQ_RADIO_TX; 00126 cts.to_me = 0; 00127 memset(cts.mac, '\0', sizeof(cts.mac)); 00128 snprintf(cts.mac, OQ_MAC_LEN, "CTS:%lld:%d|", 00129 seq, len); 00130 cts.length = (unsigned long) 00131 ceil((double) (strlen(cts.mac) + 2) * 00132 csmaca_throughput()); 00133 cts.seq_num = seq; 00134 cts.slot_time = msg.slot_time; 00135 cts.next_slot = 0; 00136 cts.code = OQ_SKB_INJECT; 00137 rx_pending = 1; 00138 } 00139 } else if (strncasecmp(msg.mac, "CTS", 3) == 0) { 00140 char *seqstr = strchr(msg.mac, ':') + 1; 00141 char *seqend = strchr(seqstr, ':'); 00142 char *lenstr = seqend + 1; 00143 char *lenend = strchr(lenstr, '|'); 00144 unsigned long long seq; 00145 unsigned int len; 00146 00147 seqend[0] = lenend[0] = '\0'; 00148 seq = strtoull(seqstr, NULL, 10); 00149 len = (int) strtoul(lenstr, NULL, 10); 00150 seqend[0] = ':'; 00151 lenend[0] = '|'; 00152 00153 if (!msg.to_me) 00154 available_slot = 1 + (int) 00155 ceil((len * csmaca_throughput()) / 00156 (double) msg.slot_time); 00157 /* we _assume_ that actual throughput is faster */ 00158 msg.code = OQ_SKB_DROP; 00159 00160 if (msg.to_me && rx_pending) { 00161 struct sock_buff pkt = rr->msgs[1]; 00162 rr->num_msgs = 2; 00163 pkt.tx_rx = OQ_RADIO_TX; 00164 pkt.to_me = 0; 00165 memset(pkt.mac, '\0', sizeof(pkt.mac)); 00166 snprintf(pkt.mac, OQ_MAC_LEN, "PKT:%lld|", 00167 seq); 00168 pkt.length = (unsigned long) 00169 ceil((double) (strlen(pkt.mac) + 00170 2 + len) * 00171 csmaca_throughput()); 00172 pkt.seq_num = seq; 00173 pkt.slot_time = msg.slot_time; 00174 pkt.next_slot = 0; 00175 pkt.code = OQ_SKB_SEND; 00176 tx_pending = 1; 00177 } 00178 } else if (strncasecmp(msg.mac, "PKT", 3) == 0) { 00179 char *seqstr = strchr(msg.mac, ':') + 1; 00180 char *seqend = strchr(seqstr, '|'); 00181 unsigned long long seq; 00182 00183 seqend[0] = '\0'; 00184 seq = strtoull(seqstr, NULL, 10); 00185 seqend[0] = '|'; 00186 00187 available_slot = 1; 00188 msg.code = OQ_SKB_RECV; 00189 00190 if (msg.to_me && rx_pending && tx_pending) { 00191 struct sock_buff ack = rr->msgs[1]; 00192 rr->num_msgs = 2; 00193 ack.tx_rx = OQ_RADIO_TX; 00194 ack.to_me = 0; 00195 memset(ack.mac, '\0', sizeof(ack.mac)); 00196 snprintf(ack.mac, OQ_MAC_LEN, "ACK:%lld|", 00197 seq); 00198 ack.length = (unsigned long) 00199 ceil((double) (strlen(ack.mac) + 2) * 00200 csmaca_throughput()); 00201 ack.seq_num = seq; 00202 ack.slot_time = msg.slot_time; 00203 ack.next_slot = 0; 00204 ack.code = OQ_SKB_INJECT; 00205 } 00206 } else if (strncasecmp(msg.mac, "ACK", 3) == 0) { 00207 char *seqstr = strchr(msg.mac, ':') + 1; 00208 char *seqend = strchr(seqstr, '|'); 00209 unsigned long seq; 00210 00211 seqend[0] = '\0'; 00212 seq = strtoul(seqstr, NULL, 10); 00213 seqend[0] = '|'; 00214 00215 available_slot = 0; 00216 msg.code = OQ_SKB_DROP; 00217 00218 if (msg.to_me && rx_pending && tx_pending) { 00219 struct sock_buff zilch = rr->msgs[1]; 00220 rr->num_msgs = 2; 00221 zilch.tx_rx = 0; 00222 zilch.to_me = 0; 00223 memset(zilch.mac, '\0', sizeof(zilch.mac)); 00224 zilch.length = 0; 00225 zilch.seq_num = seq; 00226 zilch.slot_time = 0; 00227 zilch.next_slot = 0; 00228 zilch.code = OQ_SKB_RELEASE; 00229 rx_pending = 0; 00230 tx_pending = 0; 00231 } 00232 } else /* abnormal packet, discard */ 00233 msg.code = OQ_SKB_DROP; 00234 } else if (msg.tx_rx == OQ_RADIO_TX) { 00235 msg.to_me = 0; 00236 memset(msg.mac, '\0', sizeof(msg.mac)); 00237 msg.length = 0; 00238 msg.seq_num = sequence++; 00239 msg.slot_time = oq_slot; 00240 msg.next_slot = 3; 00241 msg.code = OQ_SKB_WAIT; 00242 00243 if (!rx_pending && !tx_pending) { 00244 struct sock_buff rts = rr->msgs[1]; 00245 rr->num_msgs = 2; 00246 rts.tx_rx = OQ_RADIO_TX; 00247 rts.to_me = 0; 00248 memset(rts.mac, '\0', sizeof(rts.mac)); 00249 snprintf(rts.mac, OQ_MAC_LEN, "RTS:%lld:%d|", 00250 msg.seq_num, rr->size); 00251 rts.length = (unsigned long) 00252 ceil((double) (strlen(rts.mac) + 2) * 00253 csmaca_throughput()); 00254 rts.seq_num = msg.seq_num; 00255 rts.slot_time = msg.slot_time; 00256 rts.next_slot = 0; 00257 rts.code = OQ_SKB_INJECT; 00258 00259 msg.code = OQ_SKB_INJECT; 00260 } else { 00261 available_slot = 3 + (int) 00262 ceil(msg.length / (double) msg.slot_time); 00263 msg.next_slot = (int)(pow(2, msg.slot_idx) * 00264 (rand() / (double)RAND_MAX)) 00265 + available_slot; 00266 msg.slot_idx++; 00267 } 00268 } else /* impossible, discard */ 00269 msg.code = OQ_SKB_DROP; 00270 00271 return 0; 00272 }