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Diffstat (limited to 'astraceroute.c')
-rw-r--r--astraceroute.c150
1 files changed, 106 insertions, 44 deletions
diff --git a/astraceroute.c b/astraceroute.c
index 21e9a90..d70802a 100644
--- a/astraceroute.c
+++ b/astraceroute.c
@@ -266,56 +266,128 @@ static void __assemble_data(uint8_t *packet, size_t len, const char *payload)
}
}
-static void __assemble_icmp4(uint8_t *packet, size_t len)
+static void __assemble_icmp4(uint8_t *packet, size_t len, const struct ctx *ctx)
{
+ uint8_t *data;
+ size_t data_len;
struct icmphdr *icmph = (struct icmphdr *) packet;
- bug_on(len < sizeof(struct icmphdr));
+ bug_on(len < sizeof(*icmph));
icmph->type = ICMP_ECHO;
icmph->code = 0;
icmph->checksum = 0;
+
+ data = packet + sizeof(*icmph);
+ data_len = len - sizeof(*icmph);
+
+ __assemble_data(data, data_len, ctx->payload);
+
+ icmph->checksum = csum((unsigned short *)packet, len / 2);
}
-static void __assemble_icmp6(uint8_t *packet, size_t len)
+static void __assemble_icmp6(uint8_t *packet, size_t len, const struct ctx *ctx,
+ const struct sockaddr *dst, const struct sockaddr *src)
{
+ uint8_t *data;
+ size_t data_len;
+ struct ip6_hdr ip6hdr;
struct icmp6hdr *icmp6h = (struct icmp6hdr *) packet;
- bug_on(len < sizeof(struct icmp6hdr));
+ bug_on(len < sizeof(*icmp6h));
icmp6h->icmp6_type = ICMPV6_ECHO_REQUEST;
icmp6h->icmp6_code = 0;
icmp6h->icmp6_cksum = 0;
-}
-static void __assemble_tcp(uint8_t *packet, size_t len, int syn, int ack,
- int urg, int fin, int rst, int psh, int ecn,
- int dport)
-{
- struct tcphdr *tcph = (struct tcphdr *) packet;
+ data = packet + sizeof(*icmp6h);
+ data_len = len - sizeof(*icmp6h);
+
+ __assemble_data(data, data_len, ctx->payload);
+
+ memcpy(&ip6hdr.ip6_src, &((const struct sockaddr_in6 *) src)->sin6_addr,
+ sizeof(ip6hdr.ip6_src));
+ memcpy(&ip6hdr.ip6_dst, &((const struct sockaddr_in6 *) dst)->sin6_addr,
+ sizeof(ip6hdr.ip6_dst));
- bug_on(len < sizeof(struct tcphdr));
+ icmp6h->icmp6_cksum = p6_csum(&ip6hdr, packet, sizeof(*icmp6h) + data_len, IPPROTO_ICMPV6);
+}
+static size_t __assemble_tcp_header(struct tcphdr *tcph, const struct ctx *ctx)
+{
tcph->source = htons((uint16_t) rand());
- tcph->dest = htons((uint16_t) dport);
+ tcph->dest = htons((uint16_t) ctx->dport);
tcph->seq = htonl(rand());
- tcph->ack_seq = (!!ack ? htonl(rand()) : 0);
+ tcph->ack_seq = (!!ctx->ack ? htonl(rand()) : 0);
tcph->doff = 5;
- tcph->syn = !!syn;
- tcph->ack = !!ack;
- tcph->urg = !!urg;
- tcph->fin = !!fin;
- tcph->rst = !!rst;
- tcph->psh = !!psh;
- tcph->ece = !!ecn;
- tcph->cwr = !!ecn;
+ tcph->syn = !!ctx->syn;
+ tcph->ack = !!ctx->ack;
+ tcph->urg = !!ctx->urg;
+ tcph->fin = !!ctx->fin;
+ tcph->rst = !!ctx->rst;
+ tcph->psh = !!ctx->psh;
+ tcph->ece = !!ctx->ecn;
+ tcph->cwr = !!ctx->ecn;
tcph->window = htons((uint16_t) (100 + (rand() % 65435)));
- tcph->urg_ptr = (!!urg ? htons((uint16_t) rand()) : 0);
tcph->check = 0;
+ tcph->urg_ptr = (!!ctx->urg ? htons((uint16_t) rand()) : 0);
+
+ return tcph->doff * 4;
+}
+
+static void __assemble_tcp(uint8_t *packet, size_t len, const struct ctx *ctx,
+ const struct sockaddr *dst, const struct sockaddr *src)
+{
+
+ uint8_t *data;
+ size_t tcp_len, data_len;
+ struct ip iphdr;
+ struct tcphdr *tcph = (struct tcphdr *) packet;
+
+ bug_on(len < sizeof(*tcph));
+
+ tcp_len = __assemble_tcp_header(tcph, ctx);
+
+ data = packet + tcp_len;
+ data_len = len - tcp_len;
+
+ __assemble_data(data, data_len, ctx->payload);
+
+ memcpy(&iphdr.ip_src, &((const struct sockaddr_in *) src)->sin_addr.s_addr,
+ sizeof(iphdr.ip_src));
+ memcpy(&iphdr.ip_dst, &((const struct sockaddr_in *) dst)->sin_addr.s_addr,
+ sizeof(iphdr.ip_dst));
+
+ tcph->check = p4_csum(&iphdr, packet, tcp_len + data_len, IPPROTO_TCP);
+}
+
+static void __assemble_tcp6(uint8_t *packet, size_t len, const struct ctx *ctx,
+ const struct sockaddr *dst, const struct sockaddr *src)
+{
+ uint8_t *data;
+ size_t tcp_len, data_len;
+ struct ip6_hdr ip6hdr;
+ struct tcphdr *tcph = (struct tcphdr *) packet;
+
+ bug_on(len < sizeof(*tcph));
+
+ tcp_len = __assemble_tcp_header(tcph, ctx);
+
+ data = packet + tcp_len;
+ data_len = len - tcp_len;
+
+ __assemble_data(data, data_len, ctx->payload);
+
+ memcpy(&ip6hdr.ip6_src, &((const struct sockaddr_in6 *) src)->sin6_addr,
+ sizeof(ip6hdr.ip6_src));
+ memcpy(&ip6hdr.ip6_dst, &((const struct sockaddr_in6 *) dst)->sin6_addr,
+ sizeof(ip6hdr.ip6_dst));
+
+ tcph->check = p6_csum(&ip6hdr, packet, tcp_len + data_len, IPPROTO_TCP);
}
static int assemble_ipv4(uint8_t *packet, size_t len, int ttl, int proto,
@@ -323,7 +395,7 @@ static int assemble_ipv4(uint8_t *packet, size_t len, int ttl, int proto,
const struct sockaddr *src)
{
uint8_t *data;
- size_t data_len, off_next = 0;
+ size_t data_len;
struct iphdr *iph = (struct iphdr *) packet;
bug_on(!src || !dst);
@@ -345,28 +417,24 @@ static int assemble_ipv4(uint8_t *packet, size_t len, int ttl, int proto,
iph->daddr = ((const struct sockaddr_in *) dst)->sin_addr.s_addr;
iph->protocol = (uint8_t) proto;
+ iph->check = 0;
data = packet + sizeof(*iph);
data_len = len - sizeof(*iph);
switch (proto) {
case IPPROTO_TCP:
- __assemble_tcp(data, data_len, ctx->syn, ctx->ack, ctx->urg,
- ctx->fin, ctx->rst, ctx->psh, ctx->ecn, ctx->dport);
- off_next = sizeof(struct tcphdr);
+ __assemble_tcp(data, data_len, ctx, dst, src);
break;
+
case IPPROTO_ICMP:
- __assemble_icmp4(data, data_len);
- off_next = sizeof(struct icmphdr);
+ __assemble_icmp4(data, data_len, ctx);
break;
+
default:
bug();
}
- data = packet + sizeof(*iph) + off_next;
- data_len = len - sizeof(*iph) - off_next;
-
- __assemble_data(data, data_len, ctx->payload);
iph->check = csum((unsigned short *) packet, ntohs(iph->tot_len) >> 1);
@@ -378,7 +446,7 @@ static int assemble_ipv6(uint8_t *packet, size_t len, int ttl, int proto,
const struct sockaddr *src)
{
uint8_t *data;
- size_t data_len, off_next = 0;
+ size_t data_len;
struct ip6_hdr *ip6h = (struct ip6_hdr *) packet;
bug_on(!src || !dst);
@@ -403,24 +471,18 @@ static int assemble_ipv6(uint8_t *packet, size_t len, int ttl, int proto,
switch (proto) {
case IPPROTO_TCP:
- __assemble_tcp(data, data_len, ctx->syn, ctx->ack, ctx->urg,
- ctx->fin, ctx->rst, ctx->psh, ctx->ecn, ctx->dport);
- off_next = sizeof(struct tcphdr);
+ __assemble_tcp6(data, data_len, ctx, dst, src);
break;
+
case IPPROTO_ICMP:
case IPPROTO_ICMPV6:
- __assemble_icmp6(data, data_len);
- off_next = sizeof(struct icmp6hdr);
+ __assemble_icmp6(data, data_len, ctx, dst, src);
break;
+
default:
bug();
}
- data = packet + sizeof(*ip6h) + off_next;
- data_len = len - sizeof(*ip6h) - off_next;
-
- __assemble_data(data, data_len, ctx->payload);
-
return ntohl(ip6h->ip6_flow) & 0x000fffff;
}
@@ -501,7 +563,7 @@ static int check_ipv6(uint8_t *packet, size_t len, int ttl __maybe_unused,
struct ip6_hdr *ip6h_inner;
struct icmp6hdr *icmp6h;
- if (ip6h->ip6_nxt != 0x3a)
+ if (ip6h->ip6_nxt != IPPROTO_ICMPV6)
return -EINVAL;
if (memcmp(&ip6h->ip6_dst, &(((const struct sockaddr_in6 *)
ss)->sin6_addr), sizeof(ip6h->ip6_dst)))
generated by cgit v1.2.3-54-g00ecf (git 2.39.0) at 2024-11-10 09:44:48 +0000