loop.c

unix网络编程第一卷socket编程书上的全部源代码

#include	"mysdr.h"

void
loop(int sockfd, socklen_t salen)
{
	socklen_t		len;
	ssize_t			n;
	char			*p;
	struct sockaddr	*sa;
	struct sap_packet {
	  uint32_t	sap_header;
	  uint32_t	sap_src;
	  char		sap_data[BUFFSIZE];
	} buf;

	sa = Malloc(salen);

	for ( ; ; ) {
		len = salen;
		n = Recvfrom(sockfd, &buf, sizeof(buf) - 1, 0, sa, &len);
		((char *)&buf)[n] = 0;			/* null terminate */
		buf.sap_header = ntohl(buf.sap_header);

		printf("From %s hash 0x%04x\n", Sock_ntop(sa, len),
				buf.sap_header & SAP_HASH_MASK);
		if (((buf.sap_header & SAP_VERSION_MASK) >> SAP_VERSION_SHIFT) > 1) {
			err_msg("... version field not 1 (0x%08x)", buf.sap_header);
			continue;
		}
		if (buf.sap_header & SAP_IPV6) {
			err_msg("... IPv6");
			continue;
		}
		if (buf.sap_header & (SAP_DELETE|SAP_ENCRYPTED|SAP_COMPRESSED)) {
			err_msg("... can't parse this packet type (0x%08x)", buf.sap_header);
			continue;
		}
		p = buf.sap_data + ((buf.sap_header & SAP_AUTHLEN_MASK)
							>> SAP_AUTHLEN_SHIFT);
		if (strcmp(p, "application/sdp") == 0)
			p += 16;
		printf("%s\n", p);
	}
}