Function ng_pppoe_rcvdata

freebsd/netgraph/ng_pppoe.c:1411–1553

* Receive data from session hook and do something with it. */

 * Receive data from session hook and do something with it.
 */
static int
ng_pppoe_rcvdata(hook_p hook, item_p item)
{
	node_p			node = NG_HOOK_NODE(hook);
	const priv_p		privp = NG_NODE_PRIVATE(node);
	sessp			sp = NG_HOOK_PRIVATE(hook);
	struct pppoe_full_hdr	*wh;
	struct mbuf		*m;
	int			error;

	CTR6(KTR_NET, "%20s: node [%x] (%p) received %p on \"%s\" (%p)",
	    __func__, node->nd_ID, node, item, hook->hk_name, hook);

	NGI_GET_M(item, m);
	switch (sp->state) {
	case	PPPOE_NEWCONNECTED:
	case	PPPOE_CONNECTED: {
		/*
		 * Remove PPP address and control fields, if any.
		 * For example, ng_ppp(4) always sends LCP packets
		 * with address and control fields as required by
		 * generic PPP. PPPoE is an exception to the rule.
		 */
		if (m->m_pkthdr.len >= 2) {
			if (m->m_len < 2 && !(m = m_pullup(m, 2)))
				LEAVE(ENOBUFS);
			if (mtod(m, u_char *)[0] == 0xff &&
			    mtod(m, u_char *)[1] == 0x03)
				m_adj(m, 2);
		}
		/*
		 * Bang in a pre-made header, and set the length up
		 * to be correct. Then send it to the ethernet driver.
		 */
		M_PREPEND(m, sizeof(*wh), M_NOWAIT);
		if (m == NULL)
			LEAVE(ENOBUFS);

		wh = mtod(m, struct pppoe_full_hdr *);
		bcopy(&sp->pkt_hdr, wh, sizeof(*wh));
		wh->ph.length = htons(m->m_pkthdr.len - sizeof(*wh));
		NG_FWD_NEW_DATA(error, item, privp->ethernet_hook, m);
		privp->packets_out++;
		break;
		}
	case	PPPOE_PRIMED: {
		struct {
			struct pppoe_tag hdr;
			union	uniq	data;
		} __packed 	uniqtag;
		const struct pppoe_tag	*tag;
		struct mbuf 	*m0;
		const struct pppoe_hdr	*ph;
		negp		neg = sp->neg;
	        uint16_t	session;
		uint16_t	length;
		uint8_t		code;