For vendors like Juniper, extensibility for sockets is important. A
good example is socket options that aren't necessarily generic. To this end, OSD is added to the socket structure and hooks are defined for key operations on sockets. These are: o soalloc() and sodealloc() o Get and set socket options o Socket related kevent filters. One aspect about hhook that appears to be not fully baked is the return semantics (the return value from the hook is ignored in hhook_run_hooks() at the time of commit). To support return values, the socket_hhook_data structure contains a 'status' field to hold return values. Submitted by: Anuranjan Shukla <anshukla@juniper.net> Obtained from: Juniper Networks, Inc.
This commit is contained in:
Marcel Moolenaar
parent
62016143f1
commit
4ec7371233
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=270158
@ -118,7 +118,9 @@ __FBSDID("$FreeBSD$");
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#include <sys/mutex.h>
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#include <sys/domain.h>
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#include <sys/file.h> /* for struct knote */
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#include <sys/hhook.h>
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#include <sys/kernel.h>
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#include <sys/khelp.h>
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#include <sys/event.h>
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#include <sys/eventhandler.h>
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#include <sys/poll.h>
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@ -157,6 +159,7 @@ static int filt_soread(struct knote *kn, long hint);
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static void filt_sowdetach(struct knote *kn);
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static int filt_sowrite(struct knote *kn, long hint);
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static int filt_solisten(struct knote *kn, long hint);
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static int inline hhook_run_socket(struct socket *so, void *hctx, int32_t h_id);
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static struct filterops solisten_filtops = {
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.f_isfd = 1,
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@ -183,6 +186,9 @@ MALLOC_DEFINE(M_PCB, "pcb", "protocol control block");
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VNET_ASSERT(curvnet != NULL, \
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("%s:%d curvnet is NULL, so=%p", __func__, __LINE__, (so)));
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VNET_DEFINE(struct hhook_head *, socket_hhh[HHOOK_SOCKET_LAST + 1]);
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#define V_socket_hhh VNET(socket_hhh)
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/*
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* Limit on the number of connections in the listen queue waiting
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* for accept(2).
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@ -254,9 +260,20 @@ socket_zone_change(void *tag)
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maxsockets = uma_zone_set_max(socket_zone, maxsockets);
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}
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static void
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socket_hhook_register(int subtype)
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{
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if (hhook_head_register(HHOOK_TYPE_SOCKET, subtype,
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&V_socket_hhh[subtype],
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HHOOK_NOWAIT|HHOOK_HEADISINVNET) != 0)
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printf("%s: WARNING: unable to register hook\n", __func__);
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}
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static void
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socket_init(void *tag)
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{
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int i;
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socket_zone = uma_zcreate("socket", sizeof(struct socket), NULL, NULL,
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NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
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@ -264,6 +281,11 @@ socket_init(void *tag)
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uma_zone_set_warning(socket_zone, "kern.ipc.maxsockets limit reached");
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EVENTHANDLER_REGISTER(maxsockets_change, socket_zone_change, NULL,
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EVENTHANDLER_PRI_FIRST);
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/* We expect a contiguous range */
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for (i = 0; i <= HHOOK_SOCKET_LAST; i++) {
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socket_hhook_register(i);
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}
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}
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SYSINIT(socket, SI_SUB_PROTO_DOMAININIT, SI_ORDER_ANY, socket_init, NULL);
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@ -333,6 +355,11 @@ soalloc(struct vnet *vnet)
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return (NULL);
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}
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#endif
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if (khelp_init_osd(HELPER_CLASS_SOCKET, &so->osd)) {
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uma_zfree(socket_zone, so);
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return (NULL);
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}
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SOCKBUF_LOCK_INIT(&so->so_snd, "so_snd");
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SOCKBUF_LOCK_INIT(&so->so_rcv, "so_rcv");
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sx_init(&so->so_snd.sb_sx, "so_snd_sx");
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@ -348,6 +375,13 @@ soalloc(struct vnet *vnet)
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so->so_vnet = vnet;
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#endif
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mtx_unlock(&so_global_mtx);
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/* We shouldn't need the so_global_mtx */
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if (V_socket_hhh[HHOOK_SOCKET_CREATE]->hhh_nhooks > 0) {
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if (hhook_run_socket(so, NULL, HHOOK_SOCKET_CREATE))
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/* Do we need more comprehensive error returns? */
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return (NULL);
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}
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return (so);
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}
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@ -384,7 +418,11 @@ sodealloc(struct socket *so)
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#ifdef MAC
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mac_socket_destroy(so);
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#endif
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if (V_socket_hhh[HHOOK_SOCKET_CLOSE]->hhh_nhooks > 0)
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hhook_run_socket(so, NULL, HHOOK_SOCKET_CLOSE);
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crfree(so->so_cred);
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khelp_destroy_osd(&so->osd);
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sx_destroy(&so->so_snd.sb_sx);
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sx_destroy(&so->so_rcv.sb_sx);
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SOCKBUF_LOCK_DESTROY(&so->so_snd);
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@ -2327,6 +2365,25 @@ sorflush(struct socket *so)
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sbrelease_internal(&asb, so);
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}
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/*
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* Wrapper for Socket established helper hook.
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* Parameters: socket, context of the hook point, hook id.
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*/
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static int inline
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hhook_run_socket(struct socket *so, void *hctx, int32_t h_id)
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{
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struct socket_hhook_data hhook_data = {
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.so = so,
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.hctx = hctx,
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.m = NULL
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};
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hhook_run_hooks(V_socket_hhh[h_id], &hhook_data, &so->osd);
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/* Ugly but needed, since hhooks return void for now */
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return (hhook_data.status);
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}
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/*
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* Perhaps this routine, and sooptcopyout(), below, ought to come in an
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* additional variant to handle the case where the option value needs to be
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@ -2572,7 +2629,11 @@ sosetopt(struct socket *so, struct sockopt *sopt)
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break;
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default:
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error = ENOPROTOOPT;
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if (V_socket_hhh[HHOOK_SOCKET_OPT]->hhh_nhooks > 0)
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error = hhook_run_socket(so, sopt,
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HHOOK_SOCKET_OPT);
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else
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error = ENOPROTOOPT;
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break;
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}
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if (error == 0 && so->so_proto->pr_ctloutput != NULL)
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@ -2755,7 +2816,11 @@ sogetopt(struct socket *so, struct sockopt *sopt)
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goto integer;
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default:
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error = ENOPROTOOPT;
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if (V_socket_hhh[HHOOK_SOCKET_OPT]->hhh_nhooks > 0)
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error = hhook_run_socket(so, sopt,
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HHOOK_SOCKET_OPT);
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else
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error = ENOPROTOOPT;
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break;
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}
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}
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@ -3160,10 +3225,20 @@ filt_soread(struct knote *kn, long hint)
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return (1);
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} else if (so->so_error) /* temporary udp error */
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return (1);
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else if (kn->kn_sfflags & NOTE_LOWAT)
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return (kn->kn_data >= kn->kn_sdata);
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else
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return (so->so_rcv.sb_cc >= so->so_rcv.sb_lowat);
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if (kn->kn_sfflags & NOTE_LOWAT) {
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if (kn->kn_data >= kn->kn_sdata)
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return 1;
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} else {
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if (so->so_rcv.sb_cc >= so->so_rcv.sb_lowat)
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return 1;
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}
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if (V_socket_hhh[HHOOK_FILT_SOREAD]->hhh_nhooks > 0)
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/* This hook returning non-zero indicates an event, not error */
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return (hhook_run_socket(so, NULL, HHOOK_FILT_SOREAD));
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return (0);
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}
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static void
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@ -3187,6 +3262,10 @@ filt_sowrite(struct knote *kn, long hint)
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so = kn->kn_fp->f_data;
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SOCKBUF_LOCK_ASSERT(&so->so_snd);
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kn->kn_data = sbspace(&so->so_snd);
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if (V_socket_hhh[HHOOK_FILT_SOWRITE]->hhh_nhooks > 0)
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hhook_run_socket(so, kn, HHOOK_FILT_SOWRITE);
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if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
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kn->kn_flags |= EV_EOF;
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kn->kn_fflags = so->so_error;
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@ -64,6 +64,7 @@
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/* Helper hook types. */
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#define HHOOK_TYPE_TCP 1
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#define HHOOK_TYPE_SOCKET 2
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struct helper;
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struct osd;
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@ -55,6 +55,7 @@ struct osd;
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/* Helper classes. */
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#define HELPER_CLASS_TCP 0x00000001
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#define HELPER_CLASS_SOCKET 0x00000002
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/* Public KPI functions. */
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int khelp_register_helper(struct helper *h);
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@ -38,6 +38,7 @@
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#include <sys/selinfo.h> /* for struct selinfo */
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#include <sys/_lock.h>
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#include <sys/_mutex.h>
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#include <sys/osd.h>
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#include <sys/_sx.h>
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#include <sys/sockbuf.h>
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#include <sys/sockstate.h>
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@ -117,6 +118,7 @@ struct socket {
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void *so_accept_filter_arg; /* saved filter args */
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char *so_accept_filter_str; /* saved user args */
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} *so_accf;
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struct osd osd; /* Object Specific extensions */
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/*
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* so_fibnum, so_user_cookie and friends can be used to attach
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* some user-specified metadata to a socket, which then can be
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@ -292,6 +294,26 @@ MALLOC_DECLARE(M_PCB);
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MALLOC_DECLARE(M_SONAME);
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#endif
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/*
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* Socket specific helper hook point identifiers
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* Do not leave holes in the sequence, hook registration is a loop.
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*/
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#define HHOOK_SOCKET_OPT 0
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#define HHOOK_SOCKET_CREATE 1
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#define HHOOK_SOCKET_RCV 2
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#define HHOOK_SOCKET_SND 3
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#define HHOOK_FILT_SOREAD 4
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#define HHOOK_FILT_SOWRITE 5
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#define HHOOK_SOCKET_CLOSE 6
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#define HHOOK_SOCKET_LAST HHOOK_SOCKET_CLOSE
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struct socket_hhook_data {
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struct socket *so;
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struct mbuf *m;
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void *hctx; /* hook point specific data*/
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int status;
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};
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extern int maxsockets;
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extern u_long sb_max;
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extern so_gen_t so_gencnt;
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