Fixes and documentation

1 files changed, 151 insertions, 83 deletions

diff --git a/src/vpn/gnunet-dns-parser.c b/src/vpn/gnunet-dns-parser.c
index 7b81f6da4..e26638141 100644
--- a/src/vpn/gnunet-dns-parser.c
+++ b/src/vpn/gnunet-dns-parser.c
@@ -2,92 +2,160 @@
 #include "gnunet-dns-parser.h"
 #include "gnunet-vpn-packet.h"
 
-unsigned int parse_dns_name(char* d, const unsigned char* src, unsigned short idx) {/*{{{*/
-        char* dest = d;
-
-        int len = src[idx++];
-        while (len != 0) {
-                if (len & 0xC0) { /* Compressed name, offset in this and the next octet */
-                        unsigned short offset = ((len & 0x3F) << 8) | src[idx++];
-                        parse_dns_name(dest, src, offset - 12); /* 12 for the Header of the DNS-Packet, idx starts at 0 which is 12 bytes from the start of the packet */
-                        return idx;
-                }
-                memcpy(dest, src+idx, len);
-                idx += len;
-                dest += len;
-                *dest = '.';
-                dest++;
-                len = src[idx++];
-        };
-        *dest = 0;
-
-        return idx;
+/**
+ * Parse a name from DNS to a normal .-delimited, 0-terminated string.
+ *
+ * @param d The destination of the name. Should have at least 255 bytes allocated.
+ * @param src The DNS-Packet
+ * @param idx The offset inside the Packet from which on the name should be read
+ * @returns The offset of the first unparsed byte (the byte right behind the name)
+ */
+static unsigned int
+parse_dns_name(char* d, const unsigned char* src, unsigned short idx) {/*{{{*/
+    char* dest = d;
+
+    int len = src[idx++];
+    while (len != 0)
+      {
+        if (len & 0xC0)
+          { /* Compressed name, offset in this and the next octet */
+            unsigned short offset = ((len & 0x3F) << 8) | src[idx++];
+            parse_dns_name(dest, src, offset - 12); /* 12 for the Header of the DNS-Packet, idx starts at 0 which is 12 bytes from the start of the packet */
+            return idx;
+          }
+        memcpy(dest, src+idx, len);
+        idx += len;
+        dest += len;
+        *dest = '.';
+        dest++;
+        len = src[idx++];
+      };
+    *dest = 0;
+
+    return idx;
 }
 /*}}}*/
 
-unsigned short parse_dns_record(unsigned char* data, struct dns_record** dst, unsigned short count, unsigned short idx) {/*{{{*/
-        int i;
-        unsigned short _idx;
-        for (i = 0; i < count; i++) {
-                dst[i] = GNUNET_malloc(sizeof(struct dns_record));
-                dst[i]->name = alloca(255); // see RFC1035
-                char* name = dst[i]->name;
-
-                _idx = parse_dns_name(name, data, idx);
-                dst[i]->namelen = _idx - idx;
-                idx = _idx;
-
-                dst[i]->type = *((unsigned short*)(data+idx));
-                idx += 2;
-                dst[i]->class = *((unsigned short*)(data+idx));
-                idx += 2;
-                dst[i]->ttl = *((unsigned int*)(data+idx));
-                idx += 4;
-                dst[i]->data_len = *((unsigned short*)(data+idx));
-                idx += 2;
-                dst[i]->data = GNUNET_malloc(ntohs(dst[i]->data_len));
-                memcpy(dst[i]->data, data+idx, ntohs(dst[i]->data_len));
-                idx += ntohs(dst[i]->data_len);
-        }
-        return idx;
+/**
+ * Parse a complete DNS-Record from raw DNS-data to a struct dns_record
+ *
+ * @param data The DNS-data
+ * @param dst Pointer to count pointers; individual pointers will be allocated
+ * @param count Number of records to parse
+ * @param idx The offset inside the Packet from which on the name should be read
+ * @returns The offset of the first unparsed byte (the byte right behind the last record)
+ */
+static unsigned short
+parse_dns_record(unsigned char* data, /*{{{*/
+                 struct dns_record** dst,
+                 unsigned short count,
+                 unsigned short idx) {
+    int i;
+    unsigned short _idx;
+    for (i = 0; i < count; i++) {
+        dst[i] = GNUNET_malloc(sizeof(struct dns_record));
+        dst[i]->name = alloca(255); // see RFC1035, no name can be longer than this.
+        char* name = dst[i]->name;
+
+        _idx = parse_dns_name(name, data, idx);
+        dst[i]->namelen = _idx - idx;
+
+        dst[i]->name = GNUNET_malloc(dst[i]->namelen);
+        memcpy(dst[i]->name, name, dst[i]->namelen);
+
+        idx = _idx;
+
+        dst[i]->type = *((unsigned short*)(data+idx));
+        idx += 2;
+        dst[i]->class = *((unsigned short*)(data+idx));
+        idx += 2;
+        dst[i]->ttl = *((unsigned int*)(data+idx));
+        idx += 4;
+        dst[i]->data_len = *((unsigned short*)(data+idx));
+        idx += 2;
+        dst[i]->data = GNUNET_malloc(ntohs(dst[i]->data_len));
+        memcpy(dst[i]->data, data+idx, ntohs(dst[i]->data_len));
+        idx += ntohs(dst[i]->data_len);
+    }
+    return idx;
 }/*}}}*/
 
-struct dns_pkt_parsed* parse_dns_packet(struct dns_pkt* pkt) {/*{{{*/
-        struct dns_pkt_parsed* ppkt = GNUNET_malloc(sizeof(struct dns_pkt_parsed));
-        memcpy(&ppkt->s, &pkt->s, sizeof pkt->s);
-
-        unsigned short qdcount = ntohs(ppkt->s.qdcount);
-        unsigned short ancount = ntohs(ppkt->s.ancount);
-        unsigned short nscount = ntohs(ppkt->s.nscount);
-        unsigned short arcount = ntohs(ppkt->s.arcount);
-
-        ppkt->queries = GNUNET_malloc(qdcount*sizeof(struct dns_query*));
-        ppkt->answers = GNUNET_malloc(ancount*sizeof(struct dns_record*));
-        ppkt->nameservers = GNUNET_malloc(nscount*sizeof(struct dns_record*));
-        ppkt->additional = GNUNET_malloc(arcount*sizeof(struct dns_record*));
-
-        unsigned short idx = 0, _idx; /* This keeps track how far we have parsed the data */
-
-        int i;
-        for (i = 0; i < qdcount; i++) { /*{{{*/
-                ppkt->queries[i] = GNUNET_malloc(sizeof(struct dns_query));
-                char* name = alloca(255); /* see RFC1035, it can't be more than this. */
-
-                _idx = parse_dns_name(name, pkt->data, idx);
-                ppkt->queries[i]->namelen = _idx - idx;
-                idx = _idx;
-
-                ppkt->queries[i]->name = GNUNET_malloc(ppkt->queries[i]->namelen + 1);
-                memcpy(ppkt->queries[i]->name, name, ppkt->queries[i]->namelen + 1);
-
-                ppkt->queries[i]->qtype = *((unsigned short*)(pkt->data+idx));
-                idx += 2;
-                ppkt->queries[i]->qclass = *((unsigned short*)(pkt->data+idx));
-                idx += 2;
-        }
-        /*}}}*/
-        idx = parse_dns_record(pkt->data, ppkt->answers, ancount, idx);
-        idx = parse_dns_record(pkt->data, ppkt->nameservers, nscount, idx);
-        idx = parse_dns_record(pkt->data, ppkt->additional, arcount, idx);
-        return ppkt;
+/**
+ * Parse a raw DNS-Packet into an usable struct
+ */
+struct dns_pkt_parsed*
+parse_dns_packet(struct dns_pkt* pkt) {/*{{{*/
+    struct dns_pkt_parsed* ppkt = GNUNET_malloc(sizeof(struct dns_pkt_parsed));
+    memcpy(&ppkt->s, &pkt->s, sizeof pkt->s);
+
+    unsigned short qdcount = ntohs(ppkt->s.qdcount);
+    unsigned short ancount = ntohs(ppkt->s.ancount);
+    unsigned short nscount = ntohs(ppkt->s.nscount);
+    unsigned short arcount = ntohs(ppkt->s.arcount);
+
+    ppkt->queries = GNUNET_malloc(qdcount*sizeof(struct dns_query*));
+    ppkt->answers = GNUNET_malloc(ancount*sizeof(struct dns_record*));
+    ppkt->nameservers = GNUNET_malloc(nscount*sizeof(struct dns_record*));
+    ppkt->additional = GNUNET_malloc(arcount*sizeof(struct dns_record*));
+
+    unsigned short idx = 0, _idx; /* This keeps track how far we have parsed the data */
+
+    /* Parse the Query */
+    int i;
+    for (i = 0; i < qdcount; i++)
+      { /*{{{*/
+        ppkt->queries[i] = GNUNET_malloc(sizeof(struct dns_query));
+        char* name = alloca(255); /* see RFC1035, it can't be more than this. */
+
+        _idx = parse_dns_name(name, pkt->data, idx);
+        ppkt->queries[i]->namelen = _idx - idx;
+        idx = _idx;
+
+        ppkt->queries[i]->name = GNUNET_malloc(ppkt->queries[i]->namelen);
+        memcpy(ppkt->queries[i]->name, name, ppkt->queries[i]->namelen);
+
+        ppkt->queries[i]->qtype = *((unsigned short*)(pkt->data+idx));
+        idx += 2;
+        ppkt->queries[i]->qclass = *((unsigned short*)(pkt->data+idx));
+        idx += 2;
+    }
+    /*}}}*/
+    idx = parse_dns_record(pkt->data, ppkt->answers, ancount, idx);
+    idx = parse_dns_record(pkt->data, ppkt->nameservers, nscount, idx);
+    idx = parse_dns_record(pkt->data, ppkt->additional, arcount, idx);
+    return ppkt;
 }/*}}}*/
+
+void
+free_parsed_dns_packet(struct dns_pkt_parsed* ppkt) {
+    unsigned short qdcount = ntohs(ppkt->s.qdcount);
+    unsigned short ancount = ntohs(ppkt->s.ancount);
+    unsigned short nscount = ntohs(ppkt->s.nscount);
+    unsigned short arcount = ntohs(ppkt->s.arcount);
+
+    int i;
+    for (i = 0; i < qdcount; i++) {
+        GNUNET_free(ppkt->queries[i]->name);
+        GNUNET_free(ppkt->queries[i]);
+    }
+    GNUNET_free(ppkt->queries);
+    for (i = 0; i < ancount; i++) {
+        GNUNET_free(ppkt->answers[i]->name);
+        GNUNET_free(ppkt->answers[i]->data);
+        GNUNET_free(ppkt->answers[i]);
+    }
+    GNUNET_free(ppkt->answers);
+    for (i = 0; i < nscount; i++) {
+        GNUNET_free(ppkt->nameservers[i]->name);
+        GNUNET_free(ppkt->nameservers[i]->data);
+        GNUNET_free(ppkt->nameservers[i]);
+    }
+    GNUNET_free(ppkt->nameservers);
+    for (i = 0; i < arcount; i++) {
+        GNUNET_free(ppkt->additional[i]->name);
+        GNUNET_free(ppkt->additional[i]->data);
+        GNUNET_free(ppkt->additional[i]);
+    }
+    GNUNET_free(ppkt->additional);
+    GNUNET_free(ppkt);
+}