samples/bpf/sampleip_user.c

Source file repositories/reference/linux-study-clean/samples/bpf/sampleip_user.c

File Facts

System
Linux kernel
Corpus path
samples/bpf/sampleip_user.c
Extension
.c
Size
5122 bytes
Lines
235
Domain
Support Tooling And Documentation
Bucket
samples
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

struct ipcount {
	__u64 ip;
	__u32 count;
};

/* used for sorting */
struct ipcount counts[MAX_IPS];

static int count_cmp(const void *p1, const void *p2)
{
	return ((struct ipcount *)p1)->count - ((struct ipcount *)p2)->count;
}

static void print_ip_map(int fd)
{
	struct ksym *sym;
	__u64 key, next_key;
	__u32 value;
	int i, max;

	printf("%-19s %-32s %s\n", "ADDR", "KSYM", "COUNT");

	/* fetch IPs and counts */
	key = 0, i = 0;
	while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
		bpf_map_lookup_elem(fd, &next_key, &value);
		counts[i].ip = next_key;
		counts[i++].count = value;
		key = next_key;
	}
	max = i;

	/* sort and print */
	qsort(counts, max, sizeof(struct ipcount), count_cmp);
	for (i = 0; i < max; i++) {
		if (counts[i].ip > _text_addr) {
			sym = ksym_search(counts[i].ip);
			if (!sym) {
				printf("ksym not found. Is kallsyms loaded?\n");
				continue;
			}

			printf("0x%-17llx %-32s %u\n", counts[i].ip, sym->name,
			       counts[i].count);
		} else {
			printf("0x%-17llx %-32s %u\n", counts[i].ip, "(user)",
			       counts[i].count);
		}
	}

	if (max == MAX_IPS) {
		printf("WARNING: IP hash was full (max %d entries); ", max);
		printf("may have dropped samples\n");
	}
}

static void int_exit(int sig)
{
	printf("\n");
	print_ip_map(map_fd);
	exit(0);
}

int main(int argc, char **argv)
{
	int opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS, error = 1;
	struct bpf_object *obj = NULL;
	struct bpf_program *prog;
	struct bpf_link **links;
	char filename[256];

	/* process arguments */
	while ((opt = getopt(argc, argv, "F:h")) != -1) {
		switch (opt) {
		case 'F':
			freq = atoi(optarg);
			break;
		case 'h':
		default:
			usage();
			return 0;
		}
	}
	if (argc - optind == 1)
		secs = atoi(argv[optind]);
	if (freq == 0 || secs == 0) {
		usage();
		return 1;
	}

Annotation

Implementation Notes