/*- * 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 #include #include #include #include #include #include #include #include #include #include #include /*- * This is the virtual network stack allocator, which 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]); 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 storage for virtualized global variables in a new virtual network * stack instance, and copy in initial values from our 'master' copy. */ void vnet_data_init(struct vnet *vnet) { 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; } /* * Release storage for a virtual network stack instance. */ void vnet_data_destroy(struct vnet *vnet) { free(vnet->vnet_data_mem, M_VNET_DATA); vnet->vnet_data_mem = NULL; vnet->vnet_data_base = 0; } /* * 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); } struct vnet_data_copy_fn_arg { void *start; int size; }; static void vnet_data_copy_fn(struct vnet *vnet, void *arg) { struct vnet_data_copy_fn_arg *varg = arg; memcpy((void *)((uintptr_t)vnet->vnet_data_base + (uintptr_t)varg->start), varg->start, varg->size); } /* * 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_data_copy_fn_arg varg; varg.start = start; varg.size = size; vnet_foreach(vnet_data_copy_fn, &varg); } /* * 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)); }