Break out allocation of new ifindex values from if_alloc() and if_vmove(),
and centralize in a single function ifindex_alloc(). Assert the IFNET_WLOCK, and add missing IFNET_WLOCK in if_alloc(). This does not close all known races in this code. Reviewed by: bz MFC after: 3 days
This commit is contained in:
parent
28ef31c725
commit
61f6986b07
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=196553
76
sys/net/if.c
76
sys/net/if.c
@ -223,6 +223,37 @@ ifnet_byindex_ref(u_short idx)
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return (ifp);
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}
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/*
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* Allocate an ifindex array entry; return 0 on success or an error on
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* failure.
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*/
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static int
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ifindex_alloc(u_short *idxp)
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{
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u_short idx;
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IFNET_WLOCK_ASSERT();
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/*
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* Try to find an empty slot below if_index. If we fail, take the
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* next slot.
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*/
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for (idx = 1; idx <= V_if_index; idx++) {
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if (ifnet_byindex_locked(idx) == NULL)
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break;
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}
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/* Catch if_index overflow. */
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if (idx < 1)
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return (ENOSPC);
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if (idx > V_if_index)
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V_if_index = idx;
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if (V_if_index >= V_if_indexlim)
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if_grow();
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*idxp = idx;
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return (0);
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}
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static void
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ifnet_setbyindex_locked(u_short idx, struct ifnet *ifp)
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{
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@ -335,32 +366,19 @@ struct ifnet *
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if_alloc(u_char type)
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{
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struct ifnet *ifp;
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u_short idx;
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ifp = malloc(sizeof(struct ifnet), M_IFNET, M_WAITOK|M_ZERO);
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/*
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* Try to find an empty slot below if_index. If we fail, take
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* the next slot.
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*
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* XXX: should be locked!
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*/
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for (ifp->if_index = 1; ifp->if_index <= V_if_index; ifp->if_index++) {
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if (ifnet_byindex(ifp->if_index) == NULL)
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break;
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}
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/* Catch if_index overflow. */
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if (ifp->if_index < 1) {
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IFNET_WLOCK();
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if (ifindex_alloc(&idx) != 0) {
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IFNET_WUNLOCK();
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free(ifp, M_IFNET);
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return (NULL);
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}
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if (ifp->if_index > V_if_index)
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V_if_index = ifp->if_index;
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if (V_if_index >= V_if_indexlim)
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if_grow();
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IFNET_WUNLOCK();
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ifp->if_index = idx;
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ifp->if_type = type;
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ifp->if_alloctype = type;
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if (if_com_alloc[type] != NULL) {
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ifp->if_l2com = if_com_alloc[type](type, ifp);
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if (ifp->if_l2com == NULL) {
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@ -882,6 +900,7 @@ if_detach_internal(struct ifnet *ifp, int vmove)
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void
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if_vmove(struct ifnet *ifp, struct vnet *new_vnet)
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{
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u_short idx;
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/*
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* Detach from current vnet, but preserve LLADDR info, do not
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@ -907,23 +926,12 @@ if_vmove(struct ifnet *ifp, struct vnet *new_vnet)
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*/
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CURVNET_SET_QUIET(new_vnet);
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/*
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* Try to find an empty slot below if_index. If we fail, take
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* the next slot.
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*/
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IFNET_WLOCK();
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for (ifp->if_index = 1; ifp->if_index <= V_if_index; ifp->if_index++) {
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if (ifnet_byindex_locked(ifp->if_index) == NULL)
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break;
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}
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/* Catch if_index overflow. */
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if (ifp->if_index < 1)
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if (ifindex_alloc(&idx) != 0) {
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IFNET_WUNLOCK();
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panic("if_index overflow");
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if (ifp->if_index > V_if_index)
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V_if_index = ifp->if_index;
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if (V_if_index >= V_if_indexlim)
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if_grow();
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}
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ifp->if_index = idx;
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ifnet_setbyindex_locked(ifp->if_index, ifp);
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IFNET_WUNLOCK();
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