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https://github.com/eddyem/eddys_snippets.git
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77 lines
2.3 KiB
C
77 lines
2.3 KiB
C
/*
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* This file is part of the SocketCAN project.
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* Copyright 2021 Edward V. Emelianov <edward.emelianoff@gmail.com>.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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int readCAN(int sock, struct can_frame *frame){
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fd_set fds;
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struct timeval timeout;
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timeout.tv_sec = 0;
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timeout.tv_usec = 1000; // wait not more than 1millisecond
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FD_ZERO(&fds);
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FD_SET(sock, &fds);
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do{
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int rc = select(sock+1, &fds, NULL, NULL, &timeout);
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if(rc < 0){
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if(errno != EINTR){
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WARN("select()");
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return 0;
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}
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continue;
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}
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break;
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}while(1);
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if(FD_ISSET(sock, &fds)){
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return read(sock, frame, sizeof(struct can_frame));
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}
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return 0;
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}
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int sock = socket(PF_CAN, SOCK_RAW, CAN_RAW);
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if(sock < 0) ERR("Can't create socket");
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struct sockaddr_can addr;
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struct ifreq ifr;
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strcpy(ifr.ifr_name, "can0");
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if(ioctl(sock, SIOCGIFINDEX, &ifr) < 0) ERR("ioctl()");
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addr.can_family = AF_CAN;
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addr.can_ifindex = ifr.ifr_ifindex;
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if(bind(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) ERR("bind()");
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int nbytes = 0;
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struct can_frame frame = {0};
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double dt = dtime();
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do{
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nbytes = readCAN(sock, &frame);
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if(nbytes < 0) ERR("can raw socket read");
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}while(nbytes == 0 && dtime() - dt < 10.);
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printf("got frame len=%d id=%d", frame.can_dlc, frame.can_id);
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if(frame.can_dlc) printf(", data: ");
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for(int i = 0; i < frame.can_dlc; ++i)
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printf("0x%02x ", frame.data[i]);
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printf("\n");
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frame.can_dlc = 6;
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frame.can_id = 0xaa;
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const uint8_t d[] = {1, 2, 3, 4, 5, 6, 0, 0};
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memcpy(&frame.data, d, 8);
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int n = send(sock, &frame, sizeof(struct can_frame), MSG_NOSIGNAL);
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if(sizeof(struct can_frame) != n){
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printf("n=%d\n", n);
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WARN("write()");
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}
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close(sock);
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