10dc365e34
Change-Id: I92ebde397e679c7e3f8ddcf6fcecd6af5c84f629 Reviewed-on: https://cl.tvl.fyi/c/depot/+/13012 Reviewed-by: sterni <sternenseemann@systemli.org> Tested-by: BuildkiteCI
89 lines
2.7 KiB
C
89 lines
2.7 KiB
C
#define _DEFAULT_SOURCE // see getnameinfo(3), for NI_MAX*
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#define _POSIX_C_SOURCE 200112L // see getaddrinfo(3)
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#include <assert.h>
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#include <netdb.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/socket.h>
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#include <unistd.h>
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#ifndef FLIPDOT_DEBUG
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#define FLIPDOT_DEBUG 0
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#endif
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int resolve_addr(char *host, char *port, struct addrinfo **addrs) {
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struct addrinfo hints;
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memset(&hints, 0, sizeof(hints));
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hints.ai_socktype = SOCK_DGRAM;
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hints.ai_family = AF_UNSPEC;
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hints.ai_flags |= AI_NUMERICSERV;
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return getaddrinfo(host, port, &hints, addrs);
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}
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struct flipdot {
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int sockfd;
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struct addrinfo *addrs;
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};
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// Assumes all pointers in struct flipdot are not NULL which should be the case
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// for any struct returned by flipdot_open().
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void flipdot_close(struct flipdot *flipdot) {
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if (FLIPDOT_DEBUG) fprintf(stderr, "flipdot_close() called\n");
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freeaddrinfo(flipdot->addrs);
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close(flipdot->sockfd);
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free(flipdot);
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}
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// Returns NULL if some error occurred. Note that errno isn't necessarily set.
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struct flipdot *flipdot_open(char *host, in_port_t port_number) {
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char port[NI_MAXSERV];
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struct flipdot *flipdot = malloc(sizeof(struct flipdot));
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if (flipdot == NULL) goto error;
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memset(flipdot, 0, sizeof(struct flipdot));
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flipdot->sockfd = -1;
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flipdot->addrs = NULL;
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if (snprintf(port, sizeof(port), "%d", port_number) < 0) goto error;
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if (resolve_addr(host, port, &flipdot->addrs) != 0) goto error;
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flipdot->sockfd = socket(flipdot->addrs->ai_family, SOCK_DGRAM, IPPROTO_UDP);
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if (flipdot->sockfd < 0) goto error;
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if (FLIPDOT_DEBUG) {
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char resolved_ip[NI_MAXHOST], resolved_port[NI_MAXSERV];
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if (getnameinfo(flipdot->addrs->ai_addr, flipdot->addrs->ai_addrlen,
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resolved_ip, sizeof(resolved_ip), resolved_port,
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sizeof(resolved_port),
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NI_NUMERICHOST | NI_NUMERICSERV | NI_DGRAM) == 0)
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fprintf(stderr, "flipdot_open(): using %s, port %s\n", resolved_ip,
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resolved_port);
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}
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return flipdot;
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error:
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if (flipdot != NULL) {
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if (flipdot->sockfd >= 0) close(flipdot->sockfd);
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if (flipdot->addrs != NULL) freeaddrinfo(flipdot->addrs);
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free(flipdot);
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}
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return NULL;
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}
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// Send given bytes[len] to the given flipdot, returns 1 if all bytes were sent
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// and no locally detectable errors occurred, 0 otherwise.
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int8_t flipdot_send(struct flipdot *flipdot, uint8_t *bitmap,
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size_t bitmap_len) {
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ssize_t sent = sendto(flipdot->sockfd, bitmap, bitmap_len, 0,
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flipdot->addrs->ai_addr, flipdot->addrs->ai_addrlen);
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if (FLIPDOT_DEBUG) {
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fprintf(stderr, "flipdot_send(): sent %ld bytes\n", sent);
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}
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return (sent == (ssize_t)bitmap_len);
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}
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