fs/lockd/host.c

Source file repositories/reference/linux-study-clean/fs/lockd/host.c

File Facts

System
Linux kernel
Corpus path
fs/lockd/host.c
Extension
.c
Size
18813 bytes
Lines
724
Domain
Core OS
Bucket
VFS And Filesystem Core
Inferred role
Core OS: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

struct nlm_lookup_host_info {
	const int		server;		/* search for server|client */
	const struct sockaddr	*sap;		/* address to search for */
	const size_t		salen;		/* it's length */
	const unsigned short	protocol;	/* transport to search for*/
	const u32		version;	/* NLM version to search for */
	const char		*hostname;	/* remote's hostname */
	const size_t		hostname_len;	/* it's length */
	const int		noresvport;	/* use non-priv port */
	struct net		*net;		/* network namespace to bind */
	const struct cred	*cred;
};

/*
 * Hash function must work well on big- and little-endian platforms
 */
static unsigned int __nlm_hash32(const __be32 n)
{
	unsigned int hash = (__force u32)n ^ ((__force u32)n >> 16);
	return hash ^ (hash >> 8);
}

static unsigned int __nlm_hash_addr4(const struct sockaddr *sap)
{
	const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
	return __nlm_hash32(sin->sin_addr.s_addr);
}

static unsigned int __nlm_hash_addr6(const struct sockaddr *sap)
{
	const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
	const struct in6_addr addr = sin6->sin6_addr;
	return __nlm_hash32(addr.s6_addr32[0]) ^
	       __nlm_hash32(addr.s6_addr32[1]) ^
	       __nlm_hash32(addr.s6_addr32[2]) ^
	       __nlm_hash32(addr.s6_addr32[3]);
}

static unsigned int nlm_hash_address(const struct sockaddr *sap)
{
	unsigned int hash;

	switch (sap->sa_family) {
	case AF_INET:
		hash = __nlm_hash_addr4(sap);
		break;
	case AF_INET6:
		hash = __nlm_hash_addr6(sap);
		break;
	default:
		hash = 0;
	}
	return hash & (NLM_HOST_NRHASH - 1);
}

/*
 * Allocate and initialize an nlm_host.  Common to both client and server.
 */
static struct nlm_host *nlm_alloc_host(struct nlm_lookup_host_info *ni,
				       struct nsm_handle *nsm)
{
	struct nlm_host *host = NULL;
	unsigned long now = jiffies;

	if (nsm != NULL)
		refcount_inc(&nsm->sm_count);
	else {
		nsm = nsm_get_handle(ni->net, ni->sap, ni->salen,
					ni->hostname, ni->hostname_len);
		if (unlikely(nsm == NULL)) {
			dprintk("lockd: %s failed; no nsm handle\n",
				__func__);
			goto out;
		}
	}

	host = kmalloc_obj(*host);
	if (unlikely(host == NULL)) {
		dprintk("lockd: %s failed; no memory\n", __func__);
		nsm_release(nsm);
		goto out;
	}

	memcpy(nlm_addr(host), ni->sap, ni->salen);
	host->h_addrlen    = ni->salen;
	rpc_set_port(nlm_addr(host), 0);
	host->h_srcaddrlen = 0;

	host->h_rpcclnt    = NULL;
	host->h_name	   = nsm->sm_name;

Annotation

Implementation Notes