Function if_allocmulti

freebsd/net/if.c:3337–3376

* Allocate a new ifmultiaddr and initialize based on passed arguments. We * make copies of passed sockaddrs. The ifmultiaddr will not be added to * the ifnet multicast address list here, so the caller must do that and * other setup work (such as notifying the device driver). The reference * count is initialized to 1. */

 * count is initialized to 1.
 */
static struct ifmultiaddr *
if_allocmulti(struct ifnet *ifp, struct sockaddr *sa, struct sockaddr *llsa,
    int mflags)
{
	struct ifmultiaddr *ifma;
	struct sockaddr *dupsa;

	ifma = malloc(sizeof *ifma, M_IFMADDR, mflags |
	    M_ZERO);
	if (ifma == NULL)
		return (NULL);

	dupsa = malloc(sa->sa_len, M_IFMADDR, mflags);
	if (dupsa == NULL) {
		free(ifma, M_IFMADDR);
		return (NULL);
	}
	bcopy(sa, dupsa, sa->sa_len);
	ifma->ifma_addr = dupsa;

	ifma->ifma_ifp = ifp;
	ifma->ifma_refcount = 1;
	ifma->ifma_protospec = NULL;

	if (llsa == NULL) {
		ifma->ifma_lladdr = NULL;
		return (ifma);
	}

	dupsa = malloc(llsa->sa_len, M_IFMADDR, mflags);
	if (dupsa == NULL) {
		free(ifma->ifma_addr, M_IFMADDR);
		free(ifma, M_IFMADDR);
		return (NULL);
	}
	bcopy(llsa, dupsa, llsa->sa_len);
	ifma->ifma_lladdr = dupsa;

	return (ifma);
}

/*
 * if_freemulti: free ifmultiaddr structure and possibly attached related