/*- * Copyright (c) 2004-2009 University of Zagreb * Copyright (c) 2006-2009 FreeBSD Foundation * All rights reserved. * * This software was developed by the University of Zagreb and the * FreeBSD Foundation under sponsorship by the Stichting NLnet and the * FreeBSD Foundation. * * Copyright (c) 2009 Jeffrey Roberson * Copyright (c) 2009 Robert N. M. Watson * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include __FBSDID("$FreeBSD$"); #include "opt_ddb.h" #include #include #include #include #include #include #include #include #include #include #include #include #ifdef DDB #include #endif #include #include #include /*- * This file implements core functions for virtual network stacks: * * - Virtual network stack management functions. * * - Virtual network stack memory allocator, which virtualizes global * variables in the network stack * * - Virtualized SYSINIT's/SYSUNINIT's, which allow network stack subsystems * to register startup/shutdown events to be run for each virtual network * stack instance. */ MALLOC_DEFINE(M_VNET, "vnet", "network stack control block"); /* * The virtual network stack list has two read-write locks, one sleepable and * the other not, so that the list can be stablized and walked in a variety * of network stack contexts. Both must be acquired exclusively to modify * the list, but a read lock of either lock is sufficient to walk the list. */ struct rwlock vnet_rwlock; struct sx vnet_sxlock; #define VNET_LIST_WLOCK() do { \ sx_xlock(&vnet_sxlock); \ rw_wlock(&vnet_rwlock); \ } while (0) #define VNET_LIST_WUNLOCK() do { \ rw_wunlock(&vnet_rwlock); \ sx_xunlock(&vnet_sxlock); \ } while (0) struct vnet_list_head vnet_head; struct vnet *vnet0; /* * The virtual network stack allocator provides storage for virtualized * global variables. These variables are defined/declared using the * VNET_DEFINE()/VNET_DECLARE() macros, which place them in the 'set_vnet' * linker set. The details of the implementation are somewhat subtle, but * allow the majority of most network subsystems to maintain * virtualization-agnostic. * * The virtual network stack allocator handles variables in the base kernel * vs. modules in similar but different ways. In both cases, virtualized * global variables are marked as such by being declared to be part of the * vnet linker set. These "master" copies of global variables serve two * functions: * * (1) They contain static initialization or "default" values for global * variables which will be propagated to each virtual network stack * instance when created. As with normal global variables, they default * to zero-filled. * * (2) They act as unique global names by which the variable can be referred * to, regardless of network stack instance. The single global symbol * will be used to calculate the location of a per-virtual instance * variable at run-time. * * Each virtual network stack instance has a complete copy of each * virtualized global variable, stored in a malloc'd block of memory * referred to by vnet->vnet_data_mem. Critical to the design is that each * per-instance memory block is laid out identically to the master block so * that the offset of each global variable is the same across all blocks. To * optimize run-time access, a precalculated 'base' address, * vnet->vnet_data_base, is stored in each vnet, and is the amount that can * be added to the address of a 'master' instance of a variable to get to the * per-vnet instance. * * Virtualized global variables are handled in a similar manner, but as each * module has its own 'set_vnet' linker set, and we want to keep all * virtualized globals togther, we reserve space in the kernel's linker set * for potential module variables using a per-vnet character array, * 'modspace'. The virtual network stack allocator maintains a free list to * track what space in the array is free (all, initially) and as modules are * linked, allocates portions of the space to specific globals. The kernel * module linker queries the virtual network stack allocator and will * bind references of the global to the location during linking. It also * calls into the virtual network stack allocator, once the memory is * initialized, in order to propagate the new static initializations to all * existing virtual network stack instances so that the soon-to-be executing * module will find every network stack instance with proper default values. */ /* * Location of the kernel's 'set_vnet' linker set. */ extern uintptr_t *__start_set_vnet; extern uintptr_t *__stop_set_vnet; #define VNET_START (uintptr_t)&__start_set_vnet #define VNET_STOP (uintptr_t)&__stop_set_vnet /* * Number of bytes of data in the 'set_vnet' linker set, and hence the total * size of all kernel virtualized global variables, and the malloc(9) type * that will be used to allocate it. */ #define VNET_BYTES (VNET_STOP - VNET_START) MALLOC_DEFINE(M_VNET_DATA, "vnet_data", "VNET data"); /* * VNET_MODMIN is the minimum number of bytes we will reserve for the sum of * global variables across all loaded modules. As this actually sizes an * array declared as a virtualized global variable in the kernel itself, and * we want the virtualized global variable space to be page-sized, we may * have more space than that in practice. */ #define VNET_MODMIN 8192 #define VNET_SIZE roundup2(VNET_BYTES, PAGE_SIZE) #define VNET_MODSIZE (VNET_SIZE - (VNET_BYTES - VNET_MODMIN)) /* * Space to store virtualized global variables from loadable kernel modules, * and the free list to manage it. */ static VNET_DEFINE(char, modspace[VNET_MODMIN]); /* * Global lists of subsystem constructor and destructors for vnets. They are * registered via VNET_SYSINIT() and VNET_SYSUNINIT(). The lists are * protected by the vnet_sxlock global lock. */ static TAILQ_HEAD(vnet_sysinit_head, vnet_sysinit) vnet_constructors = TAILQ_HEAD_INITIALIZER(vnet_constructors); static TAILQ_HEAD(vnet_sysuninit_head, vnet_sysinit) vnet_destructors = TAILQ_HEAD_INITIALIZER(vnet_destructors); struct vnet_data_free { uintptr_t vnd_start; int vnd_len; TAILQ_ENTRY(vnet_data_free) vnd_link; }; MALLOC_DEFINE(M_VNET_DATA_FREE, "vnet_data_free", "VNET resource accounting"); static TAILQ_HEAD(, vnet_data_free) vnet_data_free_head = TAILQ_HEAD_INITIALIZER(vnet_data_free_head); static struct sx vnet_data_free_lock; /* * Allocate a virtual network stack. */ struct vnet * vnet_alloc(void) { struct vnet *vnet; vnet = malloc(sizeof(struct vnet), M_VNET, M_WAITOK | M_ZERO); vnet->vnet_magic_n = VNET_MAGIC_N; /* * Allocate storage for virtualized global variables and copy in * initial values form our 'master' copy. */ vnet->vnet_data_mem = malloc(VNET_SIZE, M_VNET_DATA, M_WAITOK); memcpy(vnet->vnet_data_mem, (void *)VNET_START, VNET_BYTES); /* * All use of vnet-specific data will immediately subtract VNET_START * from the base memory pointer, so pre-calculate that now to avoid * it on each use. */ vnet->vnet_data_base = (uintptr_t)vnet->vnet_data_mem - VNET_START; /* Initialize / attach vnet module instances. */ CURVNET_SET_QUIET(vnet); sx_xlock(&vnet_sxlock); vnet_sysinit(); CURVNET_RESTORE(); rw_wlock(&vnet_rwlock); LIST_INSERT_HEAD(&vnet_head, vnet, vnet_le); VNET_LIST_WUNLOCK(); return (vnet); } /* * Destroy a virtual network stack. */ void vnet_destroy(struct vnet *vnet) { struct ifnet *ifp, *nifp; KASSERT(vnet->vnet_sockcnt == 0, ("%s: vnet still has sockets", __func__)); VNET_LIST_WLOCK(); LIST_REMOVE(vnet, vnet_le); rw_wunlock(&vnet_rwlock); CURVNET_SET_QUIET(vnet); /* Return all inherited interfaces to their parent vnets. */ TAILQ_FOREACH_SAFE(ifp, &V_ifnet, if_link, nifp) { if (ifp->if_home_vnet != ifp->if_vnet) if_vmove(ifp, ifp->if_home_vnet); } vnet_sysuninit(); sx_xunlock(&vnet_sxlock); CURVNET_RESTORE(); /* * Release storage for the virtual network stack instance. */ free(vnet->vnet_data_mem, M_VNET_DATA); vnet->vnet_data_mem = NULL; vnet->vnet_data_base = 0; vnet->vnet_magic_n = 0xdeadbeef; free(vnet, M_VNET); } /* * Boot time initialization and allocation of virtual network stacks. */ static void vnet_init_prelink(void *arg) { rw_init(&vnet_rwlock, "vnet_rwlock"); sx_init(&vnet_sxlock, "vnet_sxlock"); LIST_INIT(&vnet_head); } SYSINIT(vnet_init_prelink, SI_SUB_VNET_PRELINK, SI_ORDER_FIRST, vnet_init_prelink, NULL); static void vnet0_init(void *arg) { /* Warn people before take off - in case we crash early. */ printf("WARNING: VIMAGE (virtualized network stack) is a highly " "experimental feature.\n"); /* * We MUST clear curvnet in vi_init_done() before going SMP, * otherwise CURVNET_SET() macros would scream about unnecessary * curvnet recursions. */ curvnet = prison0.pr_vnet = vnet0 = vnet_alloc(); } SYSINIT(vnet0_init, SI_SUB_VNET, SI_ORDER_FIRST, vnet0_init, NULL); static void vnet_init_done(void *unused) { curvnet = NULL; } SYSINIT(vnet_init_done, SI_SUB_VNET_DONE, SI_ORDER_FIRST, vnet_init_done, NULL); /* * Once on boot, initialize the modspace freelist to entirely cover modspace. */ static void vnet_data_startup(void *dummy __unused) { struct vnet_data_free *df; df = malloc(sizeof(*df), M_VNET_DATA_FREE, M_WAITOK | M_ZERO); df->vnd_start = (uintptr_t)&VNET_NAME(modspace); df->vnd_len = VNET_MODSIZE; TAILQ_INSERT_HEAD(&vnet_data_free_head, df, vnd_link); sx_init(&vnet_data_free_lock, "vnet_data alloc lock"); } SYSINIT(vnet_data, SI_SUB_KLD, SI_ORDER_FIRST, vnet_data_startup, 0); /* * When a module is loaded and requires storage for a virtualized global * variable, allocate space from the modspace free list. This interface * should be used only by the kernel linker. */ void * vnet_data_alloc(int size) { struct vnet_data_free *df; void *s; s = NULL; size = roundup2(size, sizeof(void *)); sx_xlock(&vnet_data_free_lock); TAILQ_FOREACH(df, &vnet_data_free_head, vnd_link) { if (df->vnd_len < size) continue; if (df->vnd_len == size) { s = (void *)df->vnd_start; TAILQ_REMOVE(&vnet_data_free_head, df, vnd_link); free(df, M_VNET_DATA_FREE); break; } s = (void *)df->vnd_start; df->vnd_len -= size; df->vnd_start = df->vnd_start + size; break; } sx_xunlock(&vnet_data_free_lock); return (s); } /* * Free space for a virtualized global variable on module unload. */ void vnet_data_free(void *start_arg, int size) { struct vnet_data_free *df; struct vnet_data_free *dn; uintptr_t start; uintptr_t end; size = roundup2(size, sizeof(void *)); start = (uintptr_t)start_arg; end = start + size; /* * Free a region of space and merge it with as many neighbors as * possible. Keeping the list sorted simplifies this operation. */ sx_xlock(&vnet_data_free_lock); TAILQ_FOREACH(df, &vnet_data_free_head, vnd_link) { if (df->vnd_start > end) break; /* * If we expand at the end of an entry we may have to merge * it with the one following it as well. */ if (df->vnd_start + df->vnd_len == start) { df->vnd_len += size; dn = TAILQ_NEXT(df, vnd_link); if (df->vnd_start + df->vnd_len == dn->vnd_start) { df->vnd_len += dn->vnd_len; TAILQ_REMOVE(&vnet_data_free_head, dn, vnd_link); free(dn, M_VNET_DATA_FREE); } sx_xunlock(&vnet_data_free_lock); return; } if (df->vnd_start == end) { df->vnd_start = start; df->vnd_len += size; sx_xunlock(&vnet_data_free_lock); return; } } dn = malloc(sizeof(*df), M_VNET_DATA_FREE, M_WAITOK | M_ZERO); dn->vnd_start = start; dn->vnd_len = size; if (df) TAILQ_INSERT_BEFORE(df, dn, vnd_link); else TAILQ_INSERT_TAIL(&vnet_data_free_head, dn, vnd_link); sx_xunlock(&vnet_data_free_lock); } /* * When a new virtualized global variable has been allocated, propagate its * initial value to each already-allocated virtual network stack instance. */ void vnet_data_copy(void *start, int size) { struct vnet *vnet; VNET_LIST_RLOCK(); LIST_FOREACH(vnet, &vnet_head, vnet_le) memcpy((void *)((uintptr_t)vnet->vnet_data_base + (uintptr_t)start), start, size); VNET_LIST_RUNLOCK(); } /* * Variants on sysctl_handle_foo that know how to handle virtualized global * variables: if 'arg1' is a pointer, then we transform it to the local vnet * offset. */ int vnet_sysctl_handle_int(SYSCTL_HANDLER_ARGS) { if (arg1 != NULL) arg1 = (void *)(curvnet->vnet_data_base + (uintptr_t)arg1); return (sysctl_handle_int(oidp, arg1, arg2, req)); } int vnet_sysctl_handle_opaque(SYSCTL_HANDLER_ARGS) { if (arg1 != NULL) arg1 = (void *)(curvnet->vnet_data_base + (uintptr_t)arg1); return (sysctl_handle_opaque(oidp, arg1, arg2, req)); } int vnet_sysctl_handle_string(SYSCTL_HANDLER_ARGS) { if (arg1 != NULL) arg1 = (void *)(curvnet->vnet_data_base + (uintptr_t)arg1); return (sysctl_handle_string(oidp, arg1, arg2, req)); } int vnet_sysctl_handle_uint(SYSCTL_HANDLER_ARGS) { if (arg1 != NULL) arg1 = (void *)(curvnet->vnet_data_base + (uintptr_t)arg1); return (sysctl_handle_int(oidp, arg1, arg2, req)); } /* * Support for special SYSINIT handlers registered via VNET_SYSINIT() * and VNET_SYSUNINIT(). */ void vnet_register_sysinit(void *arg) { struct vnet_sysinit *vs, *vs2; struct vnet *vnet; vs = arg; KASSERT(vs->subsystem > SI_SUB_VNET, ("vnet sysinit too early")); /* Add the constructor to the global list of vnet constructors. */ sx_xlock(&vnet_sxlock); TAILQ_FOREACH(vs2, &vnet_constructors, link) { if (vs2->subsystem > vs->subsystem) break; if (vs2->subsystem == vs->subsystem && vs2->order > vs->order) break; } if (vs2 != NULL) TAILQ_INSERT_BEFORE(vs2, vs, link); else TAILQ_INSERT_TAIL(&vnet_constructors, vs, link); /* * Invoke the constructor on all the existing vnets when it is * registered. */ VNET_FOREACH(vnet) { CURVNET_SET_QUIET(vnet); vs->func(vs->arg); CURVNET_RESTORE(); } sx_xunlock(&vnet_sxlock); } void vnet_deregister_sysinit(void *arg) { struct vnet_sysinit *vs; vs = arg; /* Remove the constructor from the global list of vnet constructors. */ sx_xlock(&vnet_sxlock); TAILQ_REMOVE(&vnet_constructors, vs, link); sx_xunlock(&vnet_sxlock); } void vnet_register_sysuninit(void *arg) { struct vnet_sysinit *vs, *vs2; vs = arg; /* Add the destructor to the global list of vnet destructors. */ sx_xlock(&vnet_sxlock); TAILQ_FOREACH(vs2, &vnet_destructors, link) { if (vs2->subsystem > vs->subsystem) break; if (vs2->subsystem == vs->subsystem && vs2->order > vs->order) break; } if (vs2 != NULL) TAILQ_INSERT_BEFORE(vs2, vs, link); else TAILQ_INSERT_TAIL(&vnet_destructors, vs, link); sx_xunlock(&vnet_sxlock); } void vnet_deregister_sysuninit(void *arg) { struct vnet_sysinit *vs; struct vnet *vnet; vs = arg; /* * Invoke the destructor on all the existing vnets when it is * deregistered. */ sx_xlock(&vnet_sxlock); VNET_FOREACH(vnet) { CURVNET_SET_QUIET(vnet); vs->func(vs->arg); CURVNET_RESTORE(); } /* Remove the destructor from the global list of vnet destructors. */ TAILQ_REMOVE(&vnet_destructors, vs, link); sx_xunlock(&vnet_sxlock); } /* * Invoke all registered vnet constructors on the current vnet. Used during * vnet construction. The caller is responsible for ensuring the new vnet is * the current vnet and that the vnet_sxlock lock is locked. */ void vnet_sysinit(void) { struct vnet_sysinit *vs; sx_assert(&vnet_sxlock, SA_LOCKED); TAILQ_FOREACH(vs, &vnet_constructors, link) { vs->func(vs->arg); } } /* * Invoke all registered vnet destructors on the current vnet. Used during * vnet destruction. The caller is responsible for ensuring the dying vnet * is the current vnet and that the vnet_sxlock lock is locked. */ void vnet_sysuninit(void) { struct vnet_sysinit *vs; sx_assert(&vnet_sxlock, SA_LOCKED); TAILQ_FOREACH_REVERSE(vs, &vnet_destructors, vnet_sysuninit_head, link) { vs->func(vs->arg); } } #ifdef DDB DB_SHOW_COMMAND(vnets, db_show_vnets) { VNET_ITERATOR_DECL(vnet_iter); #if SIZE_MAX == UINT32_MAX /* 32-bit arch */ db_printf(" vnet ifs socks\n"); #else /* 64-bit arch, most probaly... */ db_printf(" vnet ifs socks\n"); #endif VNET_FOREACH(vnet_iter) { db_printf("%p %3d %5d\n", vnet_iter, vnet_iter->vnet_ifcnt, vnet_iter->vnet_sockcnt); } } #endif