Protect link layer network interface multicast address list manipulation
using ifp->if_addr_mtx: - Initialize if_addr_mtx when ifnet is initialized. - Destroy if_addr_mtx when ifnet is torn down. - Rename ifmaof_ifpforaddr() to if_findmulti(); assert if_addr_mtx. Staticize. - Extract ifmultiaddr allocation and initialization into if_allocmulti(); accept a 'mflags' argument to indicate whether or not sleeping is permitted. This centralizes error handling and address duplication. - Extract ifmultiaddr tear-down and deallocation in if_freemulti(). - Re-structure if_addmulti() to hold if_addr_mtx around manipulation of the ifnet multicast address list and reference count manipulation. Make use of non-sleeping allocations. Annotate the fact that we only generate routing socket events for explicit address addition, not implicit link layer address addition. - Re-structure if_delmulti() to hold if_addr_mtx around manipulation of the ifnet multicast address list and reference count manipulation. Annotate the lack of a routing socket event for implicit link layer address removal. - De-spl all and sundry. Problem reported by: Ed Maste <emaste at phaedrus dot sandvine dot ca> MFC after: 1 week
This commit is contained in:
Robert Watson
parent
71997d4be4
commit
c3b31afd92
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=148652
337
sys/net/if.c
337
sys/net/if.c
@ -417,6 +417,8 @@ if_free(struct ifnet *ifp)
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{
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if_free_type(ifp, ifp->if_type);
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IF_ADDR_LOCK_DESTROY(ifp);
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}
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void
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@ -460,6 +462,7 @@ if_attach(struct ifnet *ifp)
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TASK_INIT(&ifp->if_starttask, 0, if_start_deferred, ifp);
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TASK_INIT(&ifp->if_linktask, 0, do_link_state_change, ifp);
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IF_AFDATA_LOCK_INIT(ifp);
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IF_ADDR_LOCK_INIT(ifp);
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ifp->if_afdata_initialized = 0;
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IFNET_WLOCK();
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TAILQ_INSERT_TAIL(&ifnet, ifp, if_link);
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@ -1824,99 +1827,216 @@ if_allmulti(struct ifnet *ifp, int onswitch)
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return (if_setflag(ifp, IFF_ALLMULTI, 0, &ifp->if_amcount, onswitch));
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}
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/*
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* Add a multicast listenership to the interface in question.
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* The link layer provides a routine which converts
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*/
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int
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if_addmulti(struct ifnet *ifp, struct sockaddr *sa, struct ifmultiaddr **retifma)
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static struct ifmultiaddr *
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if_findmulti(struct ifnet *ifp, struct sockaddr *sa)
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{
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struct sockaddr *llsa, *dupsa;
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int error, s;
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struct ifmultiaddr *ifma;
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/*
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* If the matching multicast address already exists
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* then don't add a new one, just add a reference
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*/
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IF_ADDR_LOCK_ASSERT(ifp);
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TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
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if (sa_equal(sa, ifma->ifma_addr)) {
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ifma->ifma_refcount++;
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if (retifma)
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*retifma = ifma;
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return 0;
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}
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if (sa_equal(ifma->ifma_addr, sa))
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break;
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}
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/*
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* Give the link layer a chance to accept/reject it, and also
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* find out which AF_LINK address this maps to, if it isn't one
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* already.
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*/
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if (ifp->if_resolvemulti != NULL) {
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error = ifp->if_resolvemulti(ifp, &llsa, sa);
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if (error) return error;
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} else {
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llsa = NULL;
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}
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return ifma;
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}
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MALLOC(ifma, struct ifmultiaddr *, sizeof *ifma, M_IFMADDR, M_WAITOK);
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MALLOC(dupsa, struct sockaddr *, sa->sa_len, M_IFMADDR, M_WAITOK);
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/*
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* Allocate a new ifmultiaddr and initialize based on passed arguments. We
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* make copies of passed sockaddrs. The ifmultiaddr will not be added to
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* the ifnet multicast address list here, so the caller must do that and
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* other setup work (such as notifying the device driver). The reference
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* count is initialized to 1.
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*/
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static struct ifmultiaddr *
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if_allocmulti(struct ifnet *ifp, struct sockaddr *sa, struct sockaddr *llsa,
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int mflags)
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{
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struct ifmultiaddr *ifma;
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struct sockaddr *dupsa;
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MALLOC(ifma, struct ifmultiaddr *, sizeof *ifma, M_IFMADDR, mflags |
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M_ZERO);
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if (ifma == NULL)
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return (NULL);
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MALLOC(dupsa, struct sockaddr *, sa->sa_len, M_IFMADDR, mflags);
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if (dupsa == NULL) {
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FREE(ifma, M_IFMADDR);
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return (NULL);
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}
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bcopy(sa, dupsa, sa->sa_len);
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ifma->ifma_addr = dupsa;
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ifma->ifma_lladdr = llsa;
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ifma->ifma_ifp = ifp;
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ifma->ifma_refcount = 1;
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ifma->ifma_protospec = NULL;
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rt_newmaddrmsg(RTM_NEWMADDR, ifma);
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if (llsa == NULL) {
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ifma->ifma_lladdr = NULL;
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return (ifma);
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}
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MALLOC(dupsa, struct sockaddr *, llsa->sa_len, M_IFMADDR, mflags);
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if (dupsa == NULL) {
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FREE(ifma->ifma_addr, M_IFMADDR);
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FREE(ifma, M_IFMADDR);
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return (NULL);
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}
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bcopy(llsa, dupsa, llsa->sa_len);
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ifma->ifma_lladdr = dupsa;
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return (ifma);
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}
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/*
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* if_freemulti: free ifmultiaddr structure and possibly attached related
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* addresses. The caller is responsible for implementing reference
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* counting, notifying the driver, handling routing messages, and releasing
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* any dependent link layer state.
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*/
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static void
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if_freemulti(struct ifmultiaddr *ifma)
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{
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KASSERT(ifma->ifma_refcount == 1, ("if_freemulti: refcount %d",
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ifma->ifma_refcount));
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KASSERT(ifma->ifma_protospec == NULL,
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("if_freemulti: protospec not NULL"));
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if (ifma->ifma_lladdr != NULL)
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FREE(ifma->ifma_lladdr, M_IFMADDR);
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FREE(ifma->ifma_addr, M_IFMADDR);
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FREE(ifma, M_IFMADDR);
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}
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/*
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* Register an additional multicast address with a network interface.
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*
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* - If the address is already present, bump the reference count on the
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* address and return.
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* - If the address is not link-layer, look up a link layer address.
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* - Allocate address structures for one or both addresses, and attach to the
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* multicast address list on the interface. If automatically adding a link
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* layer address, the protocol address will own a reference to the link
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* layer address, to be freed when it is freed.
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* - Notify the network device driver of an addition to the multicast address
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* list.
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*
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* 'sa' points to caller-owned memory with the desired multicast address.
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*
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* 'retifma' will be used to return a pointer to the resulting multicast
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* address reference, if desired.
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*/
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int
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if_addmulti(struct ifnet *ifp, struct sockaddr *sa,
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struct ifmultiaddr **retifma)
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{
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struct ifmultiaddr *ifma, *ll_ifma;
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struct sockaddr *llsa;
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int error;
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/*
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* Some network interfaces can scan the address list at
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* interrupt time; lock them out.
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* If the address is already present, return a new reference to it;
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* otherwise, allocate storage and set up a new address.
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*/
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IF_ADDR_LOCK(ifp);
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ifma = if_findmulti(ifp, sa);
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if (ifma != NULL) {
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ifma->ifma_refcount++;
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if (retifma != NULL)
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*retifma = ifma;
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IF_ADDR_UNLOCK(ifp);
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return (0);
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}
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/*
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* The address isn't already present; resolve the protocol address
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* into a link layer address, and then look that up, bump its
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* refcount or allocate an ifma for that also. If 'llsa' was
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* returned, we will need to free it later.
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*/
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llsa = NULL;
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ll_ifma = NULL;
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if (ifp->if_resolvemulti != NULL) {
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error = ifp->if_resolvemulti(ifp, &llsa, sa);
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if (error)
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goto unlock_out;
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}
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/*
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* Allocate the new address. Don't hook it up yet, as we may also
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* need to allocate a link layer multicast address.
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*/
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ifma = if_allocmulti(ifp, sa, llsa, M_NOWAIT);
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if (ifma == NULL) {
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error = ENOMEM;
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goto free_llsa_out;
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}
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/*
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* If a link layer address is found, we'll need to see if it's
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* already present in the address list, or allocate is as well.
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* When this block finishes, the link layer address will be on the
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* list.
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*/
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if (llsa != NULL) {
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ll_ifma = if_findmulti(ifp, llsa);
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if (ll_ifma == NULL) {
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ll_ifma = if_allocmulti(ifp, llsa, NULL, M_NOWAIT);
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if (ll_ifma == NULL) {
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if_freemulti(ifma);
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error = ENOMEM;
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goto free_llsa_out;
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}
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TAILQ_INSERT_HEAD(&ifp->if_multiaddrs, ll_ifma,
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ifma_link);
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} else
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ll_ifma->ifma_refcount++;
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}
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/*
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* We now have a new multicast address, ifma, and possibly a new or
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* referenced link layer address. Add the primary address to the
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* ifnet address list.
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*/
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s = splimp();
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TAILQ_INSERT_HEAD(&ifp->if_multiaddrs, ifma, ifma_link);
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splx(s);
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if (retifma != NULL)
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*retifma = ifma;
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if (llsa != NULL) {
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TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
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if (sa_equal(ifma->ifma_addr, llsa))
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break;
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}
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if (ifma) {
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ifma->ifma_refcount++;
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} else {
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MALLOC(ifma, struct ifmultiaddr *, sizeof *ifma,
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M_IFMADDR, M_WAITOK);
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MALLOC(dupsa, struct sockaddr *, llsa->sa_len,
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M_IFMADDR, M_WAITOK);
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bcopy(llsa, dupsa, llsa->sa_len);
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ifma->ifma_addr = dupsa;
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ifma->ifma_lladdr = NULL;
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ifma->ifma_ifp = ifp;
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ifma->ifma_refcount = 1;
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ifma->ifma_protospec = NULL;
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s = splimp();
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TAILQ_INSERT_HEAD(&ifp->if_multiaddrs, ifma, ifma_link);
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splx(s);
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}
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}
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/*
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* Must generate the message while holding the lock so that 'ifma'
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* pointer is still valid.
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*
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* XXXRW: How come we don't announce ll_ifma?
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*/
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rt_newmaddrmsg(RTM_NEWMADDR, ifma);
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IF_ADDR_UNLOCK(ifp);
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/*
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* We are certain we have added something, so call down to the
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* interface to let them know about it.
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*/
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if (ifp->if_ioctl != NULL) {
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s = splimp();
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IFF_LOCKGIANT(ifp);
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(void) (*ifp->if_ioctl)(ifp, SIOCADDMULTI, 0);
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IFF_UNLOCKGIANT(ifp);
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splx(s);
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}
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return 0;
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if (llsa != NULL)
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FREE(llsa, M_IFMADDR);
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return (0);
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free_llsa_out:
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if (llsa != NULL)
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FREE(llsa, M_IFMADDR);
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unlock_out:
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IF_ADDR_UNLOCK(ifp);
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return (error);
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}
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/*
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@ -1926,72 +2046,53 @@ if_addmulti(struct ifnet *ifp, struct sockaddr *sa, struct ifmultiaddr **retifma
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int
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if_delmulti(struct ifnet *ifp, struct sockaddr *sa)
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{
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struct ifmultiaddr *ifma;
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int s;
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struct ifmultiaddr *ifma, *ll_ifma;
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TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link)
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if (sa_equal(sa, ifma->ifma_addr))
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break;
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if (ifma == NULL)
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IF_ADDR_LOCK(ifp);
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ifma = if_findmulti(ifp, sa);
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if (ifma == NULL) {
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IF_ADDR_UNLOCK(ifp);
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return ENOENT;
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}
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if (ifma->ifma_refcount > 1) {
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ifma->ifma_refcount--;
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IF_ADDR_UNLOCK(ifp);
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return 0;
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}
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rt_newmaddrmsg(RTM_DELMADDR, ifma);
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sa = ifma->ifma_lladdr;
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s = splimp();
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if (sa != NULL)
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ll_ifma = if_findmulti(ifp, sa);
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else
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ll_ifma = NULL;
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/*
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* XXXRW: How come we don't announce ll_ifma?
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*/
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rt_newmaddrmsg(RTM_DELMADDR, ifma);
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TAILQ_REMOVE(&ifp->if_multiaddrs, ifma, ifma_link);
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if_freemulti(ifma);
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if (ll_ifma != NULL) {
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if (ll_ifma->ifma_refcount == 1) {
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TAILQ_REMOVE(&ifp->if_multiaddrs, ll_ifma, ifma_link);
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if_freemulti(ll_ifma);
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} else
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ll_ifma->ifma_refcount--;
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}
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IF_ADDR_UNLOCK(ifp);
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/*
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* Make sure the interface driver is notified
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* in the case of a link layer mcast group being left.
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*/
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if (ifp->if_ioctl && ifma->ifma_addr->sa_family == AF_LINK && sa == 0) {
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if (ifp->if_ioctl) {
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IFF_LOCKGIANT(ifp);
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(void) (*ifp->if_ioctl)(ifp, SIOCDELMULTI, 0);
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IFF_UNLOCKGIANT(ifp);
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}
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splx(s);
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free(ifma->ifma_addr, M_IFMADDR);
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free(ifma, M_IFMADDR);
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if (sa == NULL)
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return 0;
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/*
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* Now look for the link-layer address which corresponds to
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* this network address. It had been squirreled away in
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* ifma->ifma_lladdr for this purpose (so we don't have
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* to call ifp->if_resolvemulti() again), and we saved that
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* value in sa above. If some nasty deleted the
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* link-layer address out from underneath us, we can deal because
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* the address we stored was is not the same as the one which was
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* in the record for the link-layer address. (So we don't complain
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* in that case.)
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*/
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TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link)
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if (sa_equal(sa, ifma->ifma_addr))
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break;
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if (ifma == NULL)
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return 0;
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if (ifma->ifma_refcount > 1) {
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ifma->ifma_refcount--;
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return 0;
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}
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s = splimp();
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TAILQ_REMOVE(&ifp->if_multiaddrs, ifma, ifma_link);
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if (ifp->if_ioctl != NULL) {
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IFF_LOCKGIANT(ifp);
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(void) (*ifp->if_ioctl)(ifp, SIOCDELMULTI, 0);
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IFF_UNLOCKGIANT(ifp);
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}
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splx(s);
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free(ifma->ifma_addr, M_IFMADDR);
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free(sa, M_IFMADDR);
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free(ifma, M_IFMADDR);
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return 0;
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}
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@ -2070,18 +2171,6 @@ if_setlladdr(struct ifnet *ifp, const u_char *lladdr, int len)
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return (0);
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}
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struct ifmultiaddr *
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ifmaof_ifpforaddr(struct sockaddr *sa, struct ifnet *ifp)
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{
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struct ifmultiaddr *ifma;
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TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link)
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if (sa_equal(ifma->ifma_addr, sa))
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break;
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return ifma;
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}
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/*
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* The name argument must be a pointer to storage which will last as
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* long as the interface does. For physical devices, the result of
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@ -645,7 +645,6 @@ struct ifaddr *ifa_ifwithnet(struct sockaddr *);
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struct ifaddr *ifa_ifwithroute(int, struct sockaddr *, struct sockaddr *);
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struct ifaddr *ifaof_ifpforaddr(struct sockaddr *, struct ifnet *);
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struct ifmultiaddr *ifmaof_ifpforaddr(struct sockaddr *, struct ifnet *);
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int if_simloop(struct ifnet *ifp, struct mbuf *m, int af, int hlen);
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typedef void *if_com_alloc_t(u_char type, struct ifnet *ifp);
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