net/packet/af_packet.c

2246 	unsigned short macoff, hdrlen;
2303 		macoff = netoff = TPACKET_ALIGN(po->tp_hdrlen) + 16 +
2313 		macoff = netoff - maclen;
2320 		if (macoff + snaplen > po->rx_ring.frame_size) {
2335 			snaplen = po->rx_ring.frame_size - macoff;
2341 	} else if (unlikely(macoff + snaplen >
2345 		nval = GET_PBDQC_FROM_RB(&po->rx_ring)->max_frame_len - macoff;
2346 		pr_err_once("tpacket_rcv: packet too big, clamped from %u to %u. macoff=%u\n",
2347 			    snaplen, nval, macoff);
2351 			macoff = GET_PBDQC_FROM_RB(&po->rx_ring)->max_frame_len;
2357 					TP_STATUS_KERNEL, (macoff+snaplen));
2369 	    virtio_net_hdr_from_skb(skb, h.raw + macoff -
2397 	skb_copy_bits(skb, 0, h.raw + macoff, snaplen);
2414 		h.h1->tp_mac = macoff;
2423 		h.h2->tp_mac = macoff;
2445 		h.h3->tp_mac = macoff;
2474 					macoff + snaplen);