samples/bpf/tc_l2_redirect_user.c

File Facts

System

Linux kernel

Corpus path

samples/bpf/tc_l2_redirect_user.c

Extension

.c

Size

1345 bytes

Lines

71

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.

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

Dependency Surface

• linux/unistd.h
• linux/bpf.h
• stdlib.h
• stdio.h
• unistd.h
• string.h
• errno.h
• bpf/bpf.h

Detected Declarations

• function usage
• function main

Annotated Snippet

switch (opt) {
		/* General args */
		case 'U':
			pinned_file = optarg;
			break;
		case 'i':
			ifindex = atoi(optarg);
			break;
		default:
			usage();
			goto out;
		}
	}

	if (ifindex < 0 || !pinned_file) {
		usage();
		goto out;
	}

	array_fd = bpf_obj_get(pinned_file);
	if (array_fd < 0) {
		fprintf(stderr, "bpf_obj_get(%s): %s(%d)\n",
			pinned_file, strerror(errno), errno);
		goto out;
	}

	/* bpf_tunnel_key.remote_ipv4 expects host byte orders */
	ret = bpf_map_update_elem(array_fd, &array_key, &ifindex, 0);
	if (ret) {
		perror("bpf_map_update_elem");
		goto out;
	}

out:
	if (array_fd != -1)
		close(array_fd);
	return ret;
}

Annotation

• Immediate include surface: `linux/unistd.h`, `linux/bpf.h`, `stdlib.h`, `stdio.h`, `unistd.h`, `string.h`, `errno.h`, `bpf/bpf.h`.
• Detected declarations: `function usage`, `function main`.
• Atlas domain: Support Tooling And Documentation / samples.
• Implementation status: source implementation candidate.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.