mirror of
https://github.com/yarrick/iodine.git
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rewrote READ* and PUT*; in read.c, handeling malformed compression of names
This commit is contained in:
Bjorn Andersson
parent
eb9f38f2e0
commit
4a9887c9df
86
dns.c
86
dns.c
@ -32,18 +32,20 @@
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#include <string.h>
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#include <ctype.h>
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#include "read.h"
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#include "structs.h"
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#include "dns.h"
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#include "encoding.h"
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#include "read.h"
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// For FreeBSD
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#ifndef MIN
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#define MIN(a,b) ((a)<(b)?(a):(b))
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#endif
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static int host2dns(const char *, char *, int);
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static int dns_write(int, int, char *, int, char);
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static void dns_query(int, int, char *, int);
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struct sockaddr_in peer;
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char topdomain[256];
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@ -68,7 +70,8 @@ open_dns(const char *domain, int localport, in_addr_t listen_ip)
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bzero(&addr, sizeof(addr));
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addr.sin_family = AF_INET;
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addr.sin_port = htons(localport);
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addr.sin_addr.s_addr = listen_ip; // This is already network byte order, inet_addr() or constant INADDR_ANY (==0)
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/* listen_ip already in network byte order from inet_addr, or 0 */
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addr.sin_addr.s_addr = listen_ip;
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fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
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if(fd < 0) {
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@ -88,10 +91,11 @@ open_dns(const char *domain, int localport, in_addr_t listen_ip)
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}
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// Save top domain used
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strncpy(topdomain, domain, sizeof(topdomain) - 2);
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topdomain[sizeof(topdomain) - 1] = 0;
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strncpy(topdomain, domain, sizeof(topdomain) - 1);
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topdomain[sizeof(topdomain) - 1] = '\0';
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printf("Opened UDP socket\n");
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return fd;
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}
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@ -177,7 +181,7 @@ dns_handshake(int dns_fd)
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dns_write(dns_fd, ++pingid, data, 2, 'H');
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}
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void
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static void
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dns_query(int fd, int id, char *host, int type)
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{
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char *p;
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@ -205,16 +209,16 @@ dns_query(int fd, int id, char *host, int type)
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p = buf + sizeof(HEADER);
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p += host2dns(host, p, strlen(host));
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PUTSHORT(type, p);
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PUTSHORT(C_IN, p);
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putshort(&p, type);
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putshort(&p, C_IN);
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// EDNS0
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*p++ = 0x00; //Root
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PUTSHORT(0x0029, p); // OPT
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PUTSHORT(0x1000, p); // Payload size: 4096
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PUTSHORT(0x0000, p); // Higher bits/ edns version
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PUTSHORT(0x8000, p); // Z
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PUTSHORT(0x0000, p); // Data length
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putbyte(&p, 0x00); //Root
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putshort(&p, 0x0029); // OPT
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putshort(&p, 0x1000); // Payload size: 4096
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putshort(&p, 0x0000); // Higher bits/edns version
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putshort(&p, 0x8000); // Z
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putshort(&p, 0x0000); // Data length
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peerlen = sizeof(peer);
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@ -250,6 +254,7 @@ int
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dns_read(int fd, char *buf, int buflen)
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{
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int r;
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int rv;
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long ttl;
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short rlen;
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short type;
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@ -267,6 +272,7 @@ dns_read(int fd, char *buf, int buflen)
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addrlen = sizeof(struct sockaddr);
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r = recvfrom(fd, packet, sizeof(packet), 0, (struct sockaddr*)&from, &addrlen);
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rv = 0;
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if(r == -1) {
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perror("recvfrom");
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} else {
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@ -281,17 +287,17 @@ dns_read(int fd, char *buf, int buflen)
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rlen = 0;
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if(qdcount == 1) {
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READNAME(packet, name, data);
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READSHORT(type, data);
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READSHORT(class, data);
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readname(packet, &data, name, sizeof(name));
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readshort(packet, &data, &type);
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readshort(packet, &data, &class);
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}
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if(ancount == 1) {
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READNAME(packet, name, data);
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READSHORT(type, data);
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READSHORT(class, data);
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READLONG(ttl, data);
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READSHORT(rlen, data);
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READDATA(rdata, data, rlen);
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readname(packet, &data, name, sizeof(name));
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readshort(packet, &data, &type);
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readshort(packet, &data, &class);
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readlong(packet, &data, &ttl);
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readshort(packet, &data, &rlen);
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readdata(packet, &data, rdata, rlen);
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}
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if (dns_sending() && chunkid == ntohs(header->id)) {
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// Got ACK on sent packet
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@ -309,14 +315,12 @@ dns_read(int fd, char *buf, int buflen)
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if(type == T_NULL && rlen > 2) {
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memcpy(buf, rdata, rlen);
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return rlen;
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} else {
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return 0;
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rv = rlen;
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}
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}
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}
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return 0;
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return rv;
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}
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static int
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@ -375,19 +379,18 @@ dnsd_send(int fd, struct query *q, char *data, int datalen)
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name = 0xc000 | ((p - buf) & 0x3fff);
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p += host2dns(q->name, p, strlen(q->name));
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PUTSHORT(q->type, p);
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PUTSHORT(C_IN, p);
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putshort(&p, q->type);
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putshort(&p, C_IN);
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PUTSHORT(name, p);
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PUTSHORT(q->type, p);
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PUTSHORT(C_IN, p);
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PUTLONG(0, p);
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putshort(&p, name);
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putshort(&p, q->type);
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putshort(&p, C_IN);
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putlong(&p, 0);
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q->id = 0;
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PUTSHORT(datalen, p);
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memcpy(p, data, datalen);
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p += datalen;
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putshort(&p, datalen);
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putdata(&p, data, datalen);
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len = p - buf;
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sendto(fd, buf, len, 0, (struct sockaddr*)&q->from, q->fromlen);
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@ -411,6 +414,7 @@ int
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dnsd_read(int fd, struct query *q, char *buf, int buflen)
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{
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int r;
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int rv;
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short id;
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short type;
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short class;
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@ -436,10 +440,9 @@ dnsd_read(int fd, struct query *q, char *buf, int buflen)
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qdcount = ntohs(header->qdcount);
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if(qdcount == 1) {
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bzero(name, sizeof(name));
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READNAME(packet, name, data);
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READSHORT(type, data);
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READSHORT(class, data);
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readname(packet, &data, name, sizeof(name));
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readshort(packet, &data, &type);
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readshort(packet, &data, &class);
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strncpy(q->name, name, 256);
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q->type = type;
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@ -447,12 +450,13 @@ dnsd_read(int fd, struct query *q, char *buf, int buflen)
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q->fromlen = addrlen;
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memcpy((struct sockaddr*)&q->from, (struct sockaddr*)&from, addrlen);
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return decodepacket(name, buf, buflen);
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rv = decodepacket(name, buf, buflen);
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}
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}
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} else {
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perror("recvfrom");
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rv = 0;
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}
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return 0;
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return rv;
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}
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1
dns.h
1
dns.h
@ -25,7 +25,6 @@ int dns_sending();
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void dns_handle_tun(int, char *, int);
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void dns_ping(int);
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void dns_handshake(int);
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void dns_query(int, int, char *, int);
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int dns_read(int, char *, int);
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extern struct sockaddr_in peer;
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125
read.c
125
read.c
@ -17,38 +17,129 @@
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#include <string.h>
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int
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readname(char *packet, char *dst, char *src)
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readname(char *packet, char **src, char *dst, size_t length)
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{
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char l;
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char *dummy;
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int len;
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int offset;
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char *p;
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char c;
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len = 0;
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while(*src) {
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l = *src++;
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len++;
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p = *src;
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if(l & 0x80 && l & 0x40) {
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offset = ((src[-1] & 0x3f) << 8) | src[0];
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readname(packet, dst, packet + offset);
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dst += strlen(dst);
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p = *src;
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while(*p && len < length) {
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c = *p++;
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/* is this a compressed label? */
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if((c & 0xc0) == 0xc0) {
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dummy = packet + (((p[-1] & 0x3f) << 8) | p[0]);
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readname(packet, &dummy, dst, length - len);
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break;
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}
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while(l) {
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*dst++ = *src++;
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l--;
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while(c && len < length) {
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*dst++ = *p++;
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len++;
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c--;
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}
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*dst++ = '.';
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if (*p != 0)
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*dst = '.';
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else
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*dst = '\0';
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}
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(*src) = p+1;
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*dst = '\0';
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src++;
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len++;
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return strlen(dst);
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}
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int
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readshort(char *packet, char **src, short *dst)
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{
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char *p;
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p = *src;
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*dst = ((short)p[0] << 8)
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| ((short)p[1]);
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(*src) += sizeof(short);
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return sizeof(short);
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}
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int
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readlong(char *packet, char **src, long *dst)
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{
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char *p;
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p = *src;
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*dst = ((long)p[0] << 24)
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| ((long)p[1] << 16)
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| ((long)p[2] << 8)
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| ((long)p[3]);
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(*src) += sizeof(long);
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return sizeof(long);
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}
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int
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readdata(char *packet, char **src, char *dst, size_t len)
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{
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memcpy(dst, *src, len);
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(*src) += len;
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return len;
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}
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int
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putbyte(char **dst, char value)
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{
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**dst = value;
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(*dst)++;
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return sizeof(char);
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}
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int
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putshort(char **dst, short value)
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{
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char *p;
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p = *dst;
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*p++ = (value >> 8);
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*p++ = value;
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(*dst) = p;
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return sizeof(short);
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}
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int
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putlong(char **dst, long value)
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{
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char *p;
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p = *dst;
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*p++ = (value >> 24);
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*p++ = (value >> 16);
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*p++ = (value >> 8);
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*p++ = (value);
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(*dst) = p;
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return sizeof(long);
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}
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int
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putdata(char **dst, char *data, size_t len)
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{
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memcpy(*dst, data, len);
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(*dst) += len;
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return len;
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}
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21
read.h
21
read.h
@ -17,19 +17,14 @@
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#ifndef _READ_H_
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#define _READ_H_
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int readname(char *, char *, char *);
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int readname(char *, char **, char *, size_t);
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int readshort(char *, char **, short *);
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int readlong(char *, char **, long *);
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int readdata(char *, char **, char *, size_t);
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#define READNAME(packet, dst, src) (src) += readname((packet), (dst), (src));
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#define READSHORT(dst, src) \
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memcpy(&dst, src, 2); \
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(dst) = ntohs(dst); (src)+=2;
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#define READLONG(dst, src) \
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memcpy(&dst, src, 2); \
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(dst) = ntohl(dst); (src)+=4;
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#define READDATA(dst, src, len) \
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memcpy((dst), (src), (len)); (src)+=(len);
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int putbyte(char **, char);
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int putshort(char **, short);
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int putlong(char **, long);
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int putdata(char **, char *, size_t);
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#endif
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