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additional fixes

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PoliEcho
2026-09-18 22:41:12 +02:00
parent 7c4d977a62
commit 33d833dd74
1 changed files with 7 additions and 7 deletions
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src/main.c
+7 -7
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@@ -221,9 +221,7 @@ int xdp_drop_prog(struct xdp_md *ctx) {
// check SYN
if (tcp_flags & SYN_MASK) {
bpf_printk("packet is SYN\n");
if (/*mulberry32_at((__u32)time_seed, dst_port) % 3 == 0*/1) {
bpf_printk("DROPING!\n");
if (mulberry32_at((__u32)time_seed, dst_port) % 3 == 0) {
__u16 *src_port_ptr = (__u16 *)(tcp_packet_data + TCP_SRC_PORT_OFFSET);
const __u16 src_port = bpf_ntohs(*src_port_ptr);
@@ -263,6 +261,9 @@ int xdp_drop_prog(struct xdp_md *ctx) {
*(__u8 *)(ip_packet_data + IPV4_TTL_OFFSET) = DEFAULT_TTL;
// set ID
*(__u16 *)(ip_packet_data + IPV4_ID_OFFSET) = bpf_get_prandom_u32();
{ // calculate ipv4 header checksum
if ((*ip_packet_data & 0b00001111) != 5) {
return XDP_PASS;
@@ -282,11 +283,10 @@ int xdp_drop_prog(struct xdp_md *ctx) {
}
new_checksum = (new_checksum & 0xFFFF) + (new_checksum >> 16);
new_checksum = (new_checksum & 0xFFFF) + (new_checksum >> 16);
*ipv4_checksum_ptr = bpf_htons((__u16)new_checksum);
*ipv4_checksum_ptr = bpf_htons((__u16)~new_checksum);
}
// set ID
*(__u16*)(ip_packet_data+IPV4_ID_OFFSET) = bpf_get_prandom_u32();
struct tcp_v4_pseudo_header pseudo_header = {
@@ -338,7 +338,7 @@ int xdp_drop_prog(struct xdp_md *ctx) {
return XDP_TX;
}
} else {
bpf_printk("packet is not SYN\n");
return XDP_DROP;
}
return XDP_PASS;