Function ng_bpf_rcvmsg

freebsd/netgraph/ng_bpf.c:304–407

* Receive a control message */

 * Receive a control message
 */
static int
ng_bpf_rcvmsg(node_p node, item_p item, hook_p lasthook)
{
	struct ng_mesg *msg;
	struct ng_mesg *resp = NULL;
	int error = 0;

	NGI_GET_MSG(item, msg);
	switch (msg->header.typecookie) {
	case NGM_BPF_COOKIE:
		switch (msg->header.cmd) {
		case NGM_BPF_SET_PROGRAM:
		    {
			struct ng_bpf_hookprog *const
			    hp = (struct ng_bpf_hookprog *)msg->data;
			hook_p hook;

			/* Sanity check */
			if (msg->header.arglen < sizeof(*hp)
			    || msg->header.arglen
			      != NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len))
				ERROUT(EINVAL);

			/* Find hook */
			if ((hook = ng_findhook(node, hp->thisHook)) == NULL)
				ERROUT(ENOENT);

			/* Set new program */
			if ((error = ng_bpf_setprog(hook, hp)) != 0)
				ERROUT(error);
			break;
		    }

		case NGM_BPF_GET_PROGRAM:
		    {
			struct ng_bpf_hookprog *hp;
			hook_p hook;

			/* Sanity check */
			if (msg->header.arglen == 0)
				ERROUT(EINVAL);
			msg->data[msg->header.arglen - 1] = '\0';

			/* Find hook */
			if ((hook = ng_findhook(node, msg->data)) == NULL)
				ERROUT(ENOENT);

			/* Build response */
			hp = ((hinfo_p)NG_HOOK_PRIVATE(hook))->prog;
			NG_MKRESPONSE(resp, msg,
			    NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len), M_NOWAIT);
			if (resp == NULL)
				ERROUT(ENOMEM);
			bcopy(hp, resp->data,
			   NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len));
			break;
		    }