1 #include <u.h>
2 #define NOPLAN9DEFINES
3 #include <libc.h>
4 #include <ip.h>
5 
6 #include <sys/socket.h>
7 #include <netinet/in.h>
8 
9 /*
10  *  prefix of all v4 addresses
11  *  copied from libip because libc cannot depend on libip
12  */
13 static uchar v4prefix[IPaddrlen] = {
14 	0, 0, 0, 0,
15 	0, 0, 0, 0,
16 	0, 0, 0xff, 0xff,
17 	0, 0, 0, 0
18 };
19 
20 long
21 udpread(int fd, Udphdr *hdr, void *buf, long n)
22 {
23 	struct sockaddr_in sin;
24 	socklen_t len;
25 
26 	len = sizeof sin;
27 	n = recvfrom(fd, buf, n, 0, (struct sockaddr*)&sin, &len);
28 	if(len != sizeof sin){
29 		werrstr("recvfrom acting weird");
30 		return -1;
31 	}
32 	if(n < 0)
33 		return -1;
34 	memset(hdr, 0, sizeof *hdr);
35 	memmove(hdr->raddr, v4prefix, IPaddrlen);
36 	*(u32int*)(hdr->raddr+12) = *(u32int*)&sin.sin_addr;
37 	*(u16int*)hdr->rport = *(u16int*)&sin.sin_port;
38 	return n;
39 }
40 
41 long
42 udpwrite(int fd, Udphdr *hdr, void *buf, long n)
43 {
44 	struct sockaddr_in sin;
45 
46 	memset(&sin, 0, sizeof sin);
47 	sin.sin_family = AF_INET;
48 	*(u32int*)&sin.sin_addr = *(u32int*)(hdr->raddr+12);
49 	*(u16int*)&sin.sin_port = *(u16int*)hdr->rport;
50 	return sendto(fd, buf, n, 0, (struct sockaddr*)&sin, sizeof sin);
51 }