ifnet/mbuf: provide KPI to serialize/restore m->m_pkthdr.rcvif
Supplement ifindex table with generation count and use it to
serialize & restore an ifnet pointer.
Reviewed by: kp
Differential revision: https://reviews.freebsd.org/D33266
Fun note: git show e6abef0918
This commit is contained in:
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91f44749c6
commit
e1882428dc
@ -1635,6 +1635,28 @@ m_snd_tag_destroy(struct m_snd_tag *mst)
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counter_u64_add(snd_tag_count, -1);
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}
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void
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m_rcvif_serialize(struct mbuf *m)
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{
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u_short idx, gen;
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M_ASSERTPKTHDR(m);
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idx = m->m_pkthdr.rcvif->if_index;
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gen = m->m_pkthdr.rcvif->if_idxgen;
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m->m_pkthdr.rcvidx = idx;
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m->m_pkthdr.rcvgen = gen;
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}
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struct ifnet *
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m_rcvif_restore(struct mbuf *m)
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{
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M_ASSERTPKTHDR(m);
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return ((m->m_pkthdr.rcvif = ifnet_byindexgen(m->m_pkthdr.rcvidx,
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m->m_pkthdr.rcvgen)));
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}
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/*
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* Allocate an mbuf with anonymous external pages.
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*/
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49
sys/net/if.c
49
sys/net/if.c
@ -313,7 +313,10 @@ VNET_DEFINE(struct ifgrouphead, ifg_head);
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/* Table of ifnet by index. */
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static int if_index;
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static int if_indexlim = 8;
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static struct ifnet **ifindex_table;
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static struct ifindex_entry {
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struct ifnet *ife_ifnet;
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uint16_t ife_gencnt;
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} *ifindex_table;
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SYSCTL_NODE(_net_link_generic, IFMIB_SYSTEM, system,
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CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
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@ -325,8 +328,8 @@ sysctl_ifcount(SYSCTL_HANDLER_ARGS)
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IFNET_RLOCK();
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for (int i = 1; i <= if_index; i++)
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if (ifindex_table[i] != NULL &&
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ifindex_table[i]->if_vnet == curvnet)
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if (ifindex_table[i].ife_ifnet != NULL &&
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ifindex_table[i].ife_ifnet->if_vnet == curvnet)
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rv = i;
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IFNET_RUNLOCK();
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@ -370,7 +373,7 @@ ifnet_byindex(u_int idx)
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if (__predict_false(idx > if_index))
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return (NULL);
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ifp = ck_pr_load_ptr(&ifindex_table[idx]);
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ifp = ck_pr_load_ptr(&ifindex_table[idx].ife_ifnet);
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if (curvnet != NULL && ifp != NULL && ifp->if_vnet != curvnet)
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ifp = NULL;
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@ -391,6 +394,24 @@ ifnet_byindex_ref(u_int idx)
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return (ifp);
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}
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struct ifnet *
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ifnet_byindexgen(uint16_t idx, uint16_t gen)
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{
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struct ifnet *ifp;
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NET_EPOCH_ASSERT();
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if (__predict_false(idx > if_index))
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return (NULL);
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ifp = ck_pr_load_ptr(&ifindex_table[idx].ife_ifnet);
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if (ifindex_table[idx].ife_gencnt == gen)
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return (ifp);
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else
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return (NULL);
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}
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struct ifaddr *
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ifaddr_byindex(u_short idx)
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{
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@ -571,13 +592,13 @@ if_alloc_domain(u_char type, int numa_domain)
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* next slot.
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*/
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for (idx = 1; idx <= if_index; idx++) {
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if (ifindex_table[idx] == NULL)
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if (ifindex_table[idx].ife_ifnet == NULL)
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break;
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}
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/* Catch if_index overflow. */
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if (idx >= if_indexlim) {
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struct ifnet **new, **old;
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struct ifindex_entry *new, *old;
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int newlim;
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newlim = if_indexlim * 2;
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@ -593,7 +614,8 @@ if_alloc_domain(u_char type, int numa_domain)
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if_index = idx;
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ifp->if_index = idx;
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ck_pr_store_ptr(&ifindex_table[idx], ifp);
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ifp->if_idxgen = ifindex_table[idx].ife_gencnt;
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ck_pr_store_ptr(&ifindex_table[idx].ife_ifnet, ifp);
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IFNET_WUNLOCK();
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return (ifp);
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@ -668,9 +690,10 @@ if_free(struct ifnet *ifp)
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* virtualized and interface would outlive the vnet.
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*/
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IFNET_WLOCK();
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MPASS(ifindex_table[ifp->if_index] == ifp);
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ck_pr_store_ptr(&ifindex_table[ifp->if_index], NULL);
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while (if_index > 0 && ifindex_table[if_index] == NULL)
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MPASS(ifindex_table[ifp->if_index].ife_ifnet == ifp);
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ck_pr_store_ptr(&ifindex_table[ifp->if_index].ife_ifnet, NULL);
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ifindex_table[ifp->if_index].ife_gencnt++;
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while (if_index > 0 && ifindex_table[if_index].ife_ifnet == NULL)
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if_index--;
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IFNET_WUNLOCK();
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@ -819,7 +842,7 @@ if_attach_internal(struct ifnet *ifp, bool vmove)
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struct sockaddr_dl *sdl;
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struct ifaddr *ifa;
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MPASS(ifindex_table[ifp->if_index] == ifp);
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MPASS(ifindex_table[ifp->if_index].ife_ifnet == ifp);
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#ifdef VIMAGE
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ifp->if_vnet = curvnet;
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@ -4508,8 +4531,8 @@ if_show_ifnet(struct ifnet *ifp)
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IF_DB_PRINTF("%d", if_dunit);
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IF_DB_PRINTF("%s", if_description);
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IF_DB_PRINTF("%u", if_index);
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IF_DB_PRINTF("%d", if_idxgen);
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IF_DB_PRINTF("%u", if_refcount);
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IF_DB_PRINTF("%d", if_index_reserved);
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IF_DB_PRINTF("%p", if_softc);
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IF_DB_PRINTF("%p", if_l2com);
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IF_DB_PRINTF("%p", if_llsoftc);
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@ -4564,7 +4587,7 @@ DB_SHOW_ALL_COMMAND(ifnets, db_show_all_ifnets)
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u_short idx;
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for (idx = 1; idx <= if_index; idx++) {
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ifp = ifindex_table[idx];
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ifp = ifindex_table[idx].ife_ifnet;
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if (ifp == NULL)
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continue;
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db_printf( "%20s ifp=%p\n", ifp->if_xname, ifp);
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@ -334,7 +334,7 @@ struct ifnet {
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const char *if_dname; /* driver name */
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int if_dunit; /* unit or IF_DUNIT_NONE */
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u_short if_index; /* numeric abbreviation for this if */
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short if_index_reserved; /* spare space to grow if_index */
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u_short if_idxgen; /* ... and its generation count */
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char if_xname[IFNAMSIZ]; /* external name (name + unit) */
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char *if_description; /* interface description */
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@ -644,6 +644,13 @@ extern struct sx ifnet_sxlock;
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struct ifnet *ifnet_byindex(u_int);
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struct ifnet *ifnet_byindex_ref(u_int);
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/*
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* ifnet_byindexgen() looks up ifnet by index and generation count,
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* attempting to restore a weak pointer that had been stored across
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* the epoch.
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*/
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struct ifnet *ifnet_byindexgen(uint16_t idx, uint16_t gen);
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/*
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* Given the index, ifaddr_byindex() returns the one and only
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* link-level ifaddr for the interface. You are not supposed to use
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@ -159,6 +159,10 @@ struct pkthdr {
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union {
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struct m_snd_tag *snd_tag; /* send tag, if any */
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struct ifnet *rcvif; /* rcv interface */
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struct {
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uint16_t rcvidx; /* rcv interface index ... */
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uint16_t rcvgen; /* ... and generation count */
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};
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};
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SLIST_HEAD(packet_tags, m_tag) tags; /* list of packet tags */
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int32_t len; /* total packet length */
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@ -862,6 +866,8 @@ int m_snd_tag_alloc(struct ifnet *,
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void m_snd_tag_init(struct m_snd_tag *, struct ifnet *,
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const struct if_snd_tag_sw *);
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void m_snd_tag_destroy(struct m_snd_tag *);
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void m_rcvif_serialize(struct mbuf *);
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struct ifnet *m_rcvif_restore(struct mbuf *);
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static __inline int
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m_gettype(int size)
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