53 lines
1.3 KiB
C
53 lines
1.3 KiB
C
#include <linux/if_ether.h>
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#include <linux/ip.h>
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#include <linux/in.h>
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#include <linux/tcp.h>
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#include <linux/udp.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_endian.h>
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#include "types.h"
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static inline unsigned short checksum(unsigned short *buf, int bufsz) {
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unsigned long sum = 0;
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while (bufsz > 1) {
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sum += *buf;
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buf++;
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bufsz -= 2;
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}
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if (bufsz == 1) {
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sum += *(unsigned char *) buf;
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}
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sum = (sum & 0xffff) + (sum >> 16);
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sum = (sum & 0xffff) + (sum >> 16);
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return ~sum;
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}
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static inline struct tcphdr *extract_tcp_meta(struct observed_packet *pkt, void *iph, __u64 off, void *data_end) {
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struct tcphdr *hdr = iph + off;
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if ((void *) hdr + sizeof(*hdr) > data_end) {
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return NULL;
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}
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pkt->transport_proto = TCP;
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pkt->sourcePort = bpf_ntohs(hdr->source);
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pkt->destPort = bpf_ntohs(hdr->dest);
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return hdr;
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}
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static inline struct udphdr *extract_udp_meta(struct observed_packet *pkt, void *iph, __u64 off, void *data_end) {
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struct udphdr *hdr = iph + off;
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if ((void *) hdr + sizeof(*hdr) > data_end) {
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return NULL;
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}
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pkt->transport_proto = UDP;
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pkt->sourcePort = bpf_ntohs(hdr->source);
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pkt->destPort = bpf_ntohs(hdr->dest);
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return hdr;
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}
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