samples/bpf/hbm_out_kern.c

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

File Facts

System
Linux kernel
Corpus path
samples/bpf/hbm_out_kern.c
Extension
.c
Size
5657 bytes
Lines
180
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

if (pkti.ecn || pkti.is_tcp) {
			if (credit < -MARK_THRESH)
				congestion_flag = true;
			else
				congestion_flag = false;
		} else {
			congestion_flag = true;
		}
	}

	if (congestion_flag) {
		if (bpf_skb_ecn_set_ce(skb)) {
			ecn_ce_flag = true;
		} else {
			if (pkti.is_tcp) {
				unsigned int rand = bpf_get_prandom_u32();

				if (-credit >= MARK_THRESH +
				    (rand % MARK_REGION_SIZE)) {
					// Do congestion control
					cwr_flag = true;
				}
			} else if (len > LARGE_PKT_THRESH) {
				// Problem if too many small packets?
				drop_flag = true;
			}
		}
	}

	if (qsp != NULL)
		if (qsp->no_cn)
			cwr_flag = false;

	hbm_update_stats(qsp, len, curtime, congestion_flag, drop_flag,
			 cwr_flag, ecn_ce_flag, &pkti, credit);

	if (drop_flag) {
		__sync_add_and_fetch(&(qdp->credit), len);
		rv = DROP_PKT;
	}

	if (cwr_flag)
		rv |= 2;
	return rv;
}
char _license[] SEC("license") = "GPL";

Annotation

Implementation Notes