/* include sig_alrm */ #include "udpcksum.h"## 1 ##src/udpcksum/udpcksum.c## #include ## 2 ##src/udpcksum/udpcksum.c## static sigjmp_buf jmpbuf;## 3 ##src/udpcksum/udpcksum.c## static int canjump;## 4 ##src/udpcksum/udpcksum.c## void## 5 ##src/udpcksum/udpcksum.c## sig_alrm(int signo)## 6 ##src/udpcksum/udpcksum.c## {## 7 ##src/udpcksum/udpcksum.c## if (canjump == 0)## 8 ##src/udpcksum/udpcksum.c## return;## 9 ##src/udpcksum/udpcksum.c## siglongjmp(jmpbuf, 1);## 10 ##src/udpcksum/udpcksum.c## }## 11 ##src/udpcksum/udpcksum.c## /* end sig_alrm */ /* include test_udp */ void## 12 ##src/udpcksum/udpcksum.c## test_udp(void)## 13 ##src/udpcksum/udpcksum.c## {## 14 ##src/udpcksum/udpcksum.c## volatile int nsent = 0, timeout = 3;## 15 ##src/udpcksum/udpcksum.c## struct udpiphdr *ui;## 16 ##src/udpcksum/udpcksum.c## Signal(SIGALRM, sig_alrm);## 17 ##src/udpcksum/udpcksum.c## if (sigsetjmp(jmpbuf, 1)) {## 18 ##src/udpcksum/udpcksum.c## if (nsent >= 3)## 19 ##src/udpcksum/udpcksum.c## err_quit("no response");## 20 ##src/udpcksum/udpcksum.c## printf("timeout\n");## 21 ##src/udpcksum/udpcksum.c## timeout *= 2; /* exponential backoff: 3, 6, 12 */## 22 ##src/udpcksum/udpcksum.c## }## 23 ##src/udpcksum/udpcksum.c## canjump = 1; /* siglongjmp is now OK */## 24 ##src/udpcksum/udpcksum.c## send_dns_query();## 25 ##src/udpcksum/udpcksum.c## nsent++;## 26 ##src/udpcksum/udpcksum.c## alarm(timeout);## 27 ##src/udpcksum/udpcksum.c## ui = udp_read();## 28 ##src/udpcksum/udpcksum.c## canjump = 0;## 29 ##src/udpcksum/udpcksum.c## alarm(0);## 30 ##src/udpcksum/udpcksum.c## if (ui->ui_sum == 0)## 31 ##src/udpcksum/udpcksum.c## printf("UDP checksums off\n");## 32 ##src/udpcksum/udpcksum.c## else## 33 ##src/udpcksum/udpcksum.c## printf("UDP checksums on\n");## 34 ##src/udpcksum/udpcksum.c## if (verbose)## 35 ##src/udpcksum/udpcksum.c## printf("received UDP checksum = %x\n", ntohs(ui->ui_sum));## 36 ##src/udpcksum/udpcksum.c## }## 37 ##src/udpcksum/udpcksum.c## /* end test_udp */