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Thu, 23 May 2024 22:38:07 -0700 (PDT) Received: from slk15.local.net ([49.190.141.216]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-6f8fcbe9f61sm460374b3a.110.2024.05.23.22.38.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 May 2024 22:38:07 -0700 (PDT) Sender: Duncan Roe From: Duncan Roe To: netfilter-devel@vger.kernel.org Cc: pablo@netfilter.org Subject: [PATCH libnetfilter_queue v2 11/15] src: Copy nlif-related files from libnfnetlink Date: Fri, 24 May 2024 15:37:38 +1000 Message-Id: <20240524053742.27294-12-duncan_roe@optusnet.com.au> X-Mailer: git-send-email 2.35.8 In-Reply-To: <20240524053742.27294-1-duncan_roe@optusnet.com.au> References: <20240524053742.27294-1-duncan_roe@optusnet.com.au> Precedence: bulk X-Mailing-List: netfilter-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Introduce include/libnetfilter_queue/linux_list.h and src/iftable.c. These are not exact copies: all tractable checkpatch errors are fixed. Also complete iftable.c kerneldoc to doxygen translation. This commit doesn't actually do anything with the new files. Signed-off-by: Duncan Roe --- Changes in v2: - This was originally patch 12 of 32 - Update commit message - Don't copy src/rtnl.c since it's not kept - Fix checkpatch errors on the fly. - Finish kerneldoc xlation on the fly (was patch 16 of 32). include/libnetfilter_queue/linux_list.h | 730 ++++++++++++++++++++++++ src/iftable.c | 355 ++++++++++++ 2 files changed, 1085 insertions(+) create mode 100644 include/libnetfilter_queue/linux_list.h create mode 100644 src/iftable.c diff --git a/include/libnetfilter_queue/linux_list.h b/include/libnetfilter_queue/linux_list.h new file mode 100644 index 0000000..68637c3 --- /dev/null +++ b/include/libnetfilter_queue/linux_list.h @@ -0,0 +1,730 @@ +#ifndef _LINUX_LIST_H +#define _LINUX_LIST_H + +#include + +#undef offsetof +#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER) + +/** + * container_of - cast a member of a structure out to the containing structure + * + * @ptr: the pointer to the member. + * @type: the type of the container struct this is embedded in. + * @member: the name of the member within the struct. + * + */ +#define container_of(ptr, type, member) ({ \ + typeof(((type *)0)->member) *__mptr = (ptr); \ + (type *)((char *)__mptr - offsetof(type, member)); }) + +/* + * Check at compile time that something is of a particular type. + * Always evaluates to 1 so you may use it easily in comparisons. + */ +#define typecheck(type, x) \ +({ type __dummy; \ + typeof(x) __dummy2; \ + (void)(&__dummy == &__dummy2); \ + 1; \ +}) + +#define prefetch(x) ((void)0) + +/* empty define to make this work in userspace -HW */ +#ifndef smp_wmb +#define smp_wmb() /* Comment to placate checkpatch */ +#endif + +/* + * These are non-NULL pointers that will result in page faults + * under normal circumstances, used to verify that nobody uses + * non-initialized list entries. + */ +#define LIST_POISON1 ((void *) 0x00100100) +#define LIST_POISON2 ((void *) 0x00200200) + +/* + * Simple doubly linked list implementation. + * + * Some of the internal functions ("__xxx") are useful when + * manipulating whole lists rather than single entries, as + * sometimes we already know the next/prev entries and we can + * generate better code by using them directly rather than + * using the generic single-entry routines. + */ + +struct list_head { + struct list_head *next, *prev; +}; + +#define LIST_HEAD_INIT(name) { &(name), &(name) } + +#define LIST_HEAD(name) \ + struct list_head name = LIST_HEAD_INIT(name) + +#define INIT_LIST_HEAD(ptr) do { \ + (ptr)->next = (ptr); (ptr)->prev = (ptr); \ +} while (0) + +/* + * Insert a new entry between two known consecutive entries. + * + * This is only for internal list manipulation where we know + * the prev/next entries already! + */ +static inline void __list_add(struct list_head *new, + struct list_head *prev, + struct list_head *next) +{ + next->prev = new; + new->next = next; + new->prev = prev; + prev->next = new; +} + +/** + * list_add - add a new entry + * @new: new entry to be added + * @head: list head to add it after + * + * Insert a new entry after the specified head. + * This is good for implementing stacks. + */ +static inline void list_add(struct list_head *new, struct list_head *head) +{ + __list_add(new, head, head->next); +} + +/** + * list_add_tail - add a new entry + * @new: new entry to be added + * @head: list head to add it before + * + * Insert a new entry before the specified head. + * This is useful for implementing queues. + */ +static inline void list_add_tail(struct list_head *new, struct list_head *head) +{ + __list_add(new, head->prev, head); +} + +/* + * Insert a new entry between two known consecutive entries. + * + * This is only for internal list manipulation where we know + * the prev/next entries already! + */ +static inline void __list_add_rcu(struct list_head *new, + struct list_head *prev, struct list_head *next) +{ + new->next = next; + new->prev = prev; + smp_wmb(); /* Comment to placate checkpatch */ + next->prev = new; + prev->next = new; +} + +/** + * list_add_rcu - add a new entry to rcu-protected list + * @new: new entry to be added + * @head: list head to add it after + * + * Insert a new entry after the specified head. + * This is good for implementing stacks. + * + * The caller must take whatever precautions are necessary + * (such as holding appropriate locks) to avoid racing + * with another list-mutation primitive, such as list_add_rcu() + * or list_del_rcu(), running on this same list. + * However, it is perfectly legal to run concurrently with + * the _rcu list-traversal primitives, such as + * list_for_each_entry_rcu(). + */ +static inline void list_add_rcu(struct list_head *new, struct list_head *head) +{ + __list_add_rcu(new, head, head->next); +} + +/** + * list_add_tail_rcu - add a new entry to rcu-protected list + * @new: new entry to be added + * @head: list head to add it before + * + * Insert a new entry before the specified head. + * This is useful for implementing queues. + * + * The caller must take whatever precautions are necessary + * (such as holding appropriate locks) to avoid racing + * with another list-mutation primitive, such as list_add_tail_rcu() + * or list_del_rcu(), running on this same list. + * However, it is perfectly legal to run concurrently with + * the _rcu list-traversal primitives, such as + * list_for_each_entry_rcu(). + */ +static inline void list_add_tail_rcu(struct list_head *new, + struct list_head *head) +{ + __list_add_rcu(new, head->prev, head); +} + +/* + * Delete a list entry by making the prev/next entries + * point to each other. + * + * This is only for internal list manipulation where we know + * the prev/next entries already! + */ +static inline void __list_del(struct list_head *prev, struct list_head *next) +{ + next->prev = prev; + prev->next = next; +} + +/** + * list_del - deletes entry from list. + * @entry: the element to delete from the list. + * Note: list_empty on entry does not return true after this, the entry is + * in an undefined state. + */ +static inline void list_del(struct list_head *entry) +{ + __list_del(entry->prev, entry->next); + entry->next = LIST_POISON1; + entry->prev = LIST_POISON2; +} + +/** + * list_del_rcu - deletes entry from list without re-initialization + * @entry: the element to delete from the list. + * + * Note: list_empty on entry does not return true after this, + * the entry is in an undefined state. It is useful for RCU based + * lockfree traversal. + * + * In particular, it means that we can not poison the forward + * pointers that may still be used for walking the list. + * + * The caller must take whatever precautions are necessary + * (such as holding appropriate locks) to avoid racing + * with another list-mutation primitive, such as list_del_rcu() + * or list_add_rcu(), running on this same list. + * However, it is perfectly legal to run concurrently with + * the _rcu list-traversal primitives, such as + * list_for_each_entry_rcu(). + * + * Note that the caller is not permitted to immediately free + * the newly deleted entry. Instead, either synchronize_kernel() + * or call_rcu() must be used to defer freeing until an RCU + * grace period has elapsed. + */ +static inline void list_del_rcu(struct list_head *entry) +{ + __list_del(entry->prev, entry->next); + entry->prev = LIST_POISON2; +} + +/** + * list_del_init - deletes entry from list and reinitialize it. + * @entry: the element to delete from the list. + */ +static inline void list_del_init(struct list_head *entry) +{ + __list_del(entry->prev, entry->next); + INIT_LIST_HEAD(entry); +} + +/** + * list_move - delete from one list and add as another's head + * @list: the entry to move + * @head: the head that will precede our entry + */ +static inline void list_move(struct list_head *list, struct list_head *head) +{ + __list_del(list->prev, list->next); + list_add(list, head); +} + +/** + * list_move_tail - delete from one list and add as another's tail + * @list: the entry to move + * @head: the head that will follow our entry + */ +static inline void list_move_tail(struct list_head *list, + struct list_head *head) +{ + __list_del(list->prev, list->next); + list_add_tail(list, head); +} + +/** + * list_empty - tests whether a list is empty + * @head: the list to test. + */ +static inline int list_empty(const struct list_head *head) +{ + return head->next == head; +} + +/** + * list_empty_careful - tests whether a list is + * empty _and_ checks that no other CPU might be + * in the process of still modifying either member + * + * NOTE: using list_empty_careful() without synchronization + * can only be safe if the only activity that can happen + * to the list entry is list_del_init(). Eg. it cannot be used + * if another CPU could re-list_add() it. + * + * @head: the list to test. + */ +static inline int list_empty_careful(const struct list_head *head) +{ + struct list_head *next = head->next; + + return (next == head) && (next == head->prev); +} + +static inline void __list_splice(struct list_head *list, + struct list_head *head) +{ + struct list_head *first = list->next; + struct list_head *last = list->prev; + struct list_head *at = head->next; + + first->prev = head; + head->next = first; + + last->next = at; + at->prev = last; +} + +/** + * list_splice - join two lists + * @list: the new list to add. + * @head: the place to add it in the first list. + */ +static inline void list_splice(struct list_head *list, struct list_head *head) +{ + if (!list_empty(list)) + __list_splice(list, head); +} + +/** + * list_splice_init - join two lists and reinitialise the emptied list. + * @list: the new list to add. + * @head: the place to add it in the first list. + * + * The list at @list is reinitialised + */ +static inline void list_splice_init(struct list_head *list, + struct list_head *head) +{ + if (!list_empty(list)) { + __list_splice(list, head); + INIT_LIST_HEAD(list); + } +} + +/** + * list_entry - get the struct for this entry + * @ptr: the &struct list_head pointer. + * @type: the type of the struct this is embedded in. + * @member: the name of the list_struct within the struct. + */ +#define list_entry(ptr, type, member) \ + container_of(ptr, type, member) + +/** + * list_for_each - iterate over a list + * @pos: the &struct list_head to use as a loop counter. + * @head: the head for your list. + */ +#define list_for_each(pos, head) \ + for (pos = (head)->next, prefetch(pos->next); pos != (head); \ + pos = pos->next, prefetch(pos->next)) + +/** + * __list_for_each - iterate over a list + * @pos: the &struct list_head to use as a loop counter. + * @head: the head for your list. + * + * This variant differs from list_for_each() in that it's the + * simplest possible list iteration code, no prefetching is done. + * Use this for code that knows the list to be very short (empty + * or 1 entry) most of the time. + */ +#define __list_for_each(pos, head) \ + for (pos = (head)->next; pos != (head); pos = pos->next) + +/** + * list_for_each_prev - iterate over a list backwards + * @pos: the &struct list_head to use as a loop counter. + * @head: the head for your list. + */ +#define list_for_each_prev(pos, head) \ + for (pos = (head)->prev, prefetch(pos->prev); pos != (head); \ + pos = pos->prev, prefetch(pos->prev)) + +/** + * list_for_each_safe - iterate over a list safe against removal of list entry + * @pos: the &struct list_head to use as a loop counter. + * @n: another &struct list_head to use as temporary storage + * @head: the head for your list. + */ +#define list_for_each_safe(pos, n, head) \ + for (pos = (head)->next, n = pos->next; pos != (head); \ + pos = n, n = pos->next) + +/** + * list_for_each_entry - iterate over list of given type + * @pos: the type * to use as a loop counter. + * @head: the head for your list. + * @member: the name of the list_struct within the struct. + */ +#define list_for_each_entry(pos, head, member) \ + for (pos = list_entry((head)->next, typeof(*pos), member), \ + prefetch(pos->member.next); \ + &pos->member != (head); \ + pos = list_entry(pos->member.next, typeof(*pos), member), \ + prefetch(pos->member.next)) + +/** + * list_for_each_entry_reverse - iterate backwards over list of given type. + * @pos: the type * to use as a loop counter. + * @head: the head for your list. + * @member: the name of the list_struct within the struct. + */ +#define list_for_each_entry_reverse(pos, head, member) \ + for (pos = list_entry((head)->prev, typeof(*pos), member), \ + prefetch(pos->member.prev); \ + &pos->member != (head); \ + pos = list_entry(pos->member.prev, typeof(*pos), member), \ + prefetch(pos->member.prev)) + +/** + * list_prepare_entry - prepare a pos entry for use as a start point in + * list_for_each_entry_continue + * @pos: the type * to use as a start point + * @head: the head of the list + * @member: the name of the list_struct within the struct. + */ +#define list_prepare_entry(pos, head, member) \ + ((pos) ? : list_entry(head, typeof(*pos), member)) + +/** + * list_for_each_entry_continue - iterate over list of given type + * continuing after existing point + * @pos: the type * to use as a loop counter. + * @head: the head for your list. + * @member: the name of the list_struct within the struct. + */ +#define list_for_each_entry_continue(pos, head, member) \ + for (pos = list_entry(pos->member.next, typeof(*pos), member), \ + prefetch(pos->member.next); \ + &pos->member != (head); \ + pos = list_entry(pos->member.next, typeof(*pos), member), \ + prefetch(pos->member.next)) + +/** + * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry + * @pos: the type * to use as a loop counter. + * @n: another type * to use as temporary storage + * @head: the head for your list. + * @member: the name of the list_struct within the struct. + */ +#define list_for_each_entry_safe(pos, n, head, member) \ + for (pos = list_entry((head)->next, typeof(*pos), member), \ + n = list_entry(pos->member.next, typeof(*pos), member); \ + &pos->member != (head); \ + pos = n, n = list_entry(n->member.next, typeof(*n), member)) + +/** + * list_for_each_rcu - iterate over an rcu-protected list + * @pos: the &struct list_head to use as a loop counter. + * @head: the head for your list. + * + * This list-traversal primitive may safely run concurrently with + * the _rcu list-mutation primitives such as list_add_rcu() + * as long as the traversal is guarded by rcu_read_lock(). + */ +#define list_for_each_rcu(pos, head) \ + for (pos = (head)->next, prefetch(pos->next); pos != (head); \ + pos = pos->next, ({ smp_read_barrier_depends(); 0; }), prefetch(pos->next)) + +#define __list_for_each_rcu(pos, head) \ + for (pos = (head)->next; pos != (head); \ + pos = pos->next, ({ smp_read_barrier_depends(); 0; })) + +/** + * list_for_each_safe_rcu - iterate over an rcu-protected list safe + * against removal of list entry + * @pos: the &struct list_head to use as a loop counter. + * @n: another &struct list_head to use as temporary storage + * @head: the head for your list. + * + * This list-traversal primitive may safely run concurrently with + * the _rcu list-mutation primitives such as list_add_rcu() + * as long as the traversal is guarded by rcu_read_lock(). + */ +#define list_for_each_safe_rcu(pos, n, head) \ + for (pos = (head)->next, n = pos->next; pos != (head); \ + pos = n, ({ smp_read_barrier_depends(); 0; }), n = pos->next) + +/** + * list_for_each_entry_rcu - iterate over rcu list of given type + * @pos: the type * to use as a loop counter. + * @head: the head for your list. + * @member: the name of the list_struct within the struct. + * + * This list-traversal primitive may safely run concurrently with + * the _rcu list-mutation primitives such as list_add_rcu() + * as long as the traversal is guarded by rcu_read_lock(). + */ +#define list_for_each_entry_rcu(pos, head, member) \ + for (pos = list_entry((head)->next, typeof(*pos), member), \ + prefetch(pos->member.next); \ + &pos->member != (head); \ + pos = list_entry(pos->member.next, typeof(*pos), member), \ + ({ smp_read_barrier_depends(); 0; }), \ + prefetch(pos->member.next)) + + +/** + * list_for_each_continue_rcu - iterate over an rcu-protected list + * continuing after existing point. + * @pos: the &struct list_head to use as a loop counter. + * @head: the head for your list. + * + * This list-traversal primitive may safely run concurrently with + * the _rcu list-mutation primitives such as list_add_rcu() + * as long as the traversal is guarded by rcu_read_lock(). + */ +#define list_for_each_continue_rcu(pos, head) \ + for ((pos) = (pos)->next, prefetch((pos)->next); (pos) != (head); \ + (pos) = (pos)->next, ({ smp_read_barrier_depends(); 0; }), prefetch((pos)->next)) + +/* + * Double linked lists with a single pointer list head. + * Mostly useful for hash tables where the two pointer list head is + * too wasteful. + * You lose the ability to access the tail in O(1). + */ + +struct hlist_head { + struct hlist_node *first; +}; + +struct hlist_node { + struct hlist_node *next, **pprev; +}; + +#define HLIST_HEAD_INIT { .first = NULL } +#define HLIST_HEAD(name) struct hlist_head name = { .first = NULL } +#define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL) +#define INIT_HLIST_NODE(ptr) ((ptr)->next = NULL, (ptr)->pprev = NULL) + +static inline int hlist_unhashed(const struct hlist_node *h) +{ + return !h->pprev; +} + +static inline int hlist_empty(const struct hlist_head *h) +{ + return !h->first; +} + +static inline void __hlist_del(struct hlist_node *n) +{ + struct hlist_node *next = n->next; + struct hlist_node **pprev = n->pprev; + *pprev = next; + if (next) + next->pprev = pprev; +} + +static inline void hlist_del(struct hlist_node *n) +{ + __hlist_del(n); + n->next = LIST_POISON1; + n->pprev = LIST_POISON2; +} + +/** + * hlist_del_rcu - deletes entry from hash list without re-initialization + * @n: the element to delete from the hash list. + * + * Note: list_unhashed() on entry does not return true after this, + * the entry is in an undefined state. It is useful for RCU based + * lockfree traversal. + * + * In particular, it means that we can not poison the forward + * pointers that may still be used for walking the hash list. + * + * The caller must take whatever precautions are necessary + * (such as holding appropriate locks) to avoid racing + * with another list-mutation primitive, such as hlist_add_head_rcu() + * or hlist_del_rcu(), running on this same list. + * However, it is perfectly legal to run concurrently with + * the _rcu list-traversal primitives, such as + * hlist_for_each_entry(). + */ +static inline void hlist_del_rcu(struct hlist_node *n) +{ + __hlist_del(n); + n->pprev = LIST_POISON2; +} + +static inline void hlist_del_init(struct hlist_node *n) +{ + if (n->pprev) { + __hlist_del(n); + INIT_HLIST_NODE(n); + } +} + +#define hlist_del_rcu_init hlist_del_init + +static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h) +{ + struct hlist_node *first = h->first; + + n->next = first; + if (first) + first->pprev = &n->next; + h->first = n; + n->pprev = &h->first; +} + + +/** + * hlist_add_head_rcu - adds the specified element to the specified hlist, + * while permitting racing traversals. + * @n: the element to add to the hash list. + * @h: the list to add to. + * + * The caller must take whatever precautions are necessary + * (such as holding appropriate locks) to avoid racing + * with another list-mutation primitive, such as hlist_add_head_rcu() + * or hlist_del_rcu(), running on this same list. + * However, it is perfectly legal to run concurrently with + * the _rcu list-traversal primitives, such as + * hlist_for_each_entry(), but only if smp_read_barrier_depends() + * is used to prevent memory-consistency problems on Alpha CPUs. + * Regardless of the type of CPU, the list-traversal primitive + * must be guarded by rcu_read_lock(). + * + * OK, so why don't we have an hlist_for_each_entry_rcu()??? + */ +static inline void hlist_add_head_rcu(struct hlist_node *n, + struct hlist_head *h) +{ + struct hlist_node *first = h->first; + + n->next = first; + n->pprev = &h->first; + smp_wmb(); /* Comment to placate checkpatch */ + if (first) + first->pprev = &n->next; + h->first = n; +} + +/* next must be != NULL */ +static inline void hlist_add_before(struct hlist_node *n, + struct hlist_node *next) +{ + n->pprev = next->pprev; + n->next = next; + next->pprev = &n->next; + *(n->pprev) = n; +} + +static inline void hlist_add_after(struct hlist_node *n, + struct hlist_node *next) +{ + next->next = n->next; + n->next = next; + next->pprev = &n->next; + + if (next->next) + next->next->pprev = &next->next; +} + +#define hlist_entry(ptr, type, member) container_of(ptr, type, member) + +#define hlist_for_each(pos, head) \ + for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \ + pos = pos->next) + +#define hlist_for_each_safe(pos, n, head) \ + for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \ + pos = n) + +/** + * hlist_for_each_entry - iterate over list of given type + * @tpos: the type * to use as a loop counter. + * @pos: the &struct hlist_node to use as a loop counter. + * @head: the head for your list. + * @member: the name of the hlist_node within the struct. + */ +#define hlist_for_each_entry(tpos, pos, head, member) \ + for (pos = (head)->first; \ + pos && ({ prefetch(pos->next); 1; }) && \ + ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \ + pos = pos->next) + +/** + * hlist_for_each_entry_continue - iterate over a hlist continuing after existing point + * @tpos: the type * to use as a loop counter. + * @pos: the &struct hlist_node to use as a loop counter. + * @member: the name of the hlist_node within the struct. + */ +#define hlist_for_each_entry_continue(tpos, pos, member) \ + for (pos = (pos)->next; \ + pos && ({ prefetch(pos->next); 1; }) && \ + ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \ + pos = pos->next) + +/** + * hlist_for_each_entry_from - iterate over a hlist continuing from existing point + * @tpos: the type * to use as a loop counter. + * @pos: the &struct hlist_node to use as a loop counter. + * @member: the name of the hlist_node within the struct. + */ +#define hlist_for_each_entry_from(tpos, pos, member) \ + for (; pos && ({ prefetch(pos->next); 1; }) && \ + ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \ + pos = pos->next) + +/** + * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry + * @tpos: the type * to use as a loop counter. + * @pos: the &struct hlist_node to use as a loop counter. + * @n: another &struct hlist_node to use as temporary storage + * @head: the head for your list. + * @member: the name of the hlist_node within the struct. + */ +#define hlist_for_each_entry_safe(tpos, pos, n, head, member) \ + for (pos = (head)->first; \ + pos && ({ n = pos->next; 1; }) && \ + ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \ + pos = n) + +/** + * hlist_for_each_entry_rcu - iterate over rcu list of given type + * @pos: the type * to use as a loop counter. + * @pos: the &struct hlist_node to use as a loop counter. + * @head: the head for your list. + * @member: the name of the hlist_node within the struct. + * + * This list-traversal primitive may safely run concurrently with + * the _rcu list-mutation primitives such as hlist_add_rcu() + * as long as the traversal is guarded by rcu_read_lock(). + */ +#define hlist_for_each_entry_rcu(tpos, pos, head, member) \ + for (pos = (head)->first; \ + pos && ({ prefetch(pos->next); 1; }) && \ + ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \ + pos = pos->next, ({ smp_read_barrier_depends(); 0; })) + +#endif diff --git a/src/iftable.c b/src/iftable.c new file mode 100644 index 0000000..4673001 --- /dev/null +++ b/src/iftable.c @@ -0,0 +1,355 @@ +/* iftable - table of network interfaces + * + * (C) 2004 by Astaro AG, written by Harald Welte + * (C) 2008 by Pablo Neira Ayuso + * (C) 2024 by Duncan Roe + * + * This software is Free Software and licensed under GNU GPLv2+. + */ + +/* IFINDEX handling */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include +#include "rtnl.h" +#include "linux_list.h" + +/** + * \defgroup iftable Functions to manage a table of network interfaces + * These functions maintain a database of the name and flags of each + * network interface. + * @{ + */ + +struct ifindex_node { + struct list_head head; + + uint32_t index; + uint32_t type; + uint32_t alen; + uint32_t flags; + char addr[8]; + char name[16]; +}; + +struct nlif_handle { + struct list_head ifindex_hash[16]; + struct rtnl_handle *rtnl_handle; + struct rtnl_handler ifadd_handler; + struct rtnl_handler ifdel_handler; +}; + +/* iftable_add - Add/Update an entry to/in the interface table + * \param n: netlink message header of a RTM_NEWLINK message + * \param arg: not used + * + * This function adds/updates an entry in the intrface table. + * Returns -1 on error, 1 on success. + */ +static int iftable_add(struct nlmsghdr *n, void *arg) +{ + unsigned int hash, found = 0; + struct ifinfomsg *ifi_msg = NLMSG_DATA(n); + struct ifindex_node *this; + struct rtattr *cb[IFLA_MAX+1]; + struct nlif_handle *h = arg; + + if (n->nlmsg_type != RTM_NEWLINK) + return -1; + + if (n->nlmsg_len < NLMSG_LENGTH(sizeof(ifi_msg))) + return -1; + + rtnl_parse_rtattr(cb, IFLA_MAX, IFLA_RTA(ifi_msg), IFLA_PAYLOAD(n)); + + if (!cb[IFLA_IFNAME]) + return -1; + + hash = ifi_msg->ifi_index & 0xF; + list_for_each_entry(this, &h->ifindex_hash[hash], head) { + if (this->index == ifi_msg->ifi_index) { + found = 1; + break; + } + } + + if (!found) { + this = malloc(sizeof(*this)); + if (!this) + return -1; + + this->index = ifi_msg->ifi_index; + } + + this->type = ifi_msg->ifi_type; + this->flags = ifi_msg->ifi_flags; + if (cb[IFLA_ADDRESS]) { + unsigned int alen; + + this->alen = alen = RTA_PAYLOAD(cb[IFLA_ADDRESS]); + if (alen > sizeof(this->addr)) + alen = sizeof(this->addr); + memcpy(this->addr, RTA_DATA(cb[IFLA_ADDRESS]), alen); + } else { + this->alen = 0; + memset(this->addr, 0, sizeof(this->addr)); + } + strcpy(this->name, RTA_DATA(cb[IFLA_IFNAME])); + + if (!found) + list_add(&this->head, &h->ifindex_hash[hash]); + + return 1; +} + +/* iftable_del - Delete an entry from the interface table + * \param n: netlink message header of a RTM_DELLINK nlmsg + * \param arg: not used + * + * Delete an entry from the interface table. + * Returns -1 on error, 0 if no matching entry was found or 1 on success. + */ +static int iftable_del(struct nlmsghdr *n, void *arg) +{ + struct ifinfomsg *ifi_msg = NLMSG_DATA(n); + struct rtattr *cb[IFLA_MAX+1]; + struct nlif_handle *h = arg; + struct ifindex_node *this, *tmp; + unsigned int hash; + + if (n->nlmsg_type != RTM_DELLINK) + return -1; + + if (n->nlmsg_len < NLMSG_LENGTH(sizeof(ifi_msg))) + return -1; + + rtnl_parse_rtattr(cb, IFLA_MAX, IFLA_RTA(ifi_msg), IFLA_PAYLOAD(n)); + + hash = ifi_msg->ifi_index & 0xF; + list_for_each_entry_safe(this, tmp, &h->ifindex_hash[hash], head) { + if (this->index == ifi_msg->ifi_index) { + list_del(&this->head); + free(this); + return 1; + } + } + + return 0; +} + +/** + * nlif_index2name - get the name for an ifindex + * + * \param h pointer to nlif_handle created by nlif_open() + * \param index ifindex to be resolved + * \param name interface name, pass a buffer of IFNAMSIZ size + * \return -1 on error, 1 on success + */ +int nlif_index2name(struct nlif_handle *h, + unsigned int index, + char *name) +{ + unsigned int hash; + struct ifindex_node *this; + + assert(h != NULL); + assert(name != NULL); + + if (index == 0) { + strcpy(name, "*"); + return 1; + } + + hash = index & 0xF; + list_for_each_entry(this, &h->ifindex_hash[hash], head) { + if (this->index == index) { + strcpy(name, this->name); + return 1; + } + } + + errno = ENOENT; + return -1; +} + +/** + * nlif_get_ifflags - get the flags for an ifindex + * + * \param h pointer to nlif_handle created by nlif_open() + * \param index ifindex to be resolved + * \param flags pointer to variable used to store the interface flags + * \return -1 on error, 1 on success + */ +int nlif_get_ifflags(const struct nlif_handle *h, + unsigned int index, + unsigned int *flags) +{ + unsigned int hash; + struct ifindex_node *this; + + assert(h != NULL); + assert(flags != NULL); + + if (index == 0) { + errno = ENOENT; + return -1; + } + + hash = index & 0xF; + list_for_each_entry(this, &h->ifindex_hash[hash], head) { + if (this->index == index) { + *flags = this->flags; + return 1; + } + } + errno = ENOENT; + return -1; +} + +/** + * nlif_open - initialize interface table + * + * Initialize rtnl interface and interface table + * Call this before any nlif_* function + * + * \return file descriptor to netlink socket + */ +struct nlif_handle *nlif_open(void) +{ + int i; + struct nlif_handle *h; + + h = calloc(1, sizeof(struct nlif_handle)); + if (h == NULL) + goto err; + + for (i = 0; i < 16; i++) + INIT_LIST_HEAD(&h->ifindex_hash[i]); + + h->ifadd_handler.nlmsg_type = RTM_NEWLINK; + h->ifadd_handler.handlefn = iftable_add; + h->ifadd_handler.arg = h; + h->ifdel_handler.nlmsg_type = RTM_DELLINK; + h->ifdel_handler.handlefn = iftable_del; + h->ifdel_handler.arg = h; + + h->rtnl_handle = rtnl_open(); + if (h->rtnl_handle == NULL) + goto err; + + if (rtnl_handler_register(h->rtnl_handle, &h->ifadd_handler) < 0) + goto err_close; + + if (rtnl_handler_register(h->rtnl_handle, &h->ifdel_handler) < 0) + goto err_unregister; + + return h; + +err_unregister: + rtnl_handler_unregister(h->rtnl_handle, &h->ifadd_handler); +err_close: + rtnl_close(h->rtnl_handle); + free(h); +err: + return NULL; +} + +/** + * nlif_close - free all resources associated with the interface table + * + * \param h pointer to nlif_handle created by nlif_open() + */ +void nlif_close(struct nlif_handle *h) +{ + int i; + struct ifindex_node *this, *tmp; + + assert(h != NULL); + + rtnl_handler_unregister(h->rtnl_handle, &h->ifadd_handler); + rtnl_handler_unregister(h->rtnl_handle, &h->ifdel_handler); + rtnl_close(h->rtnl_handle); + + for (i = 0; i < 16; i++) { + list_for_each_entry_safe(this, tmp, &h->ifindex_hash[i], head) { + list_del(&this->head); + free(this); + } + } + + free(h); + h = NULL; /* bugtrap */ +} + +/** + * nlif_catch - receive message from netlink and update interface table + * + * FIXME - elaborate a bit + * + * \param h pointer to nlif_handle created by nlif_open() + * \return 0 if OK + */ +int nlif_catch(struct nlif_handle *h) +{ + assert(h != NULL); + + if (h->rtnl_handle) + return rtnl_receive(h->rtnl_handle); + + return -1; +} + +static int nlif_catch_multi(struct nlif_handle *h) +{ + assert(h != NULL); + + if (h->rtnl_handle) + return rtnl_receive_multi(h->rtnl_handle); + + return -1; +} + +/** + * nlif_query - request a dump of interfaces available in the system + * \param h: pointer to a valid nlif_handler + */ +int nlif_query(struct nlif_handle *h) +{ + assert(h != NULL); + + if (rtnl_dump_type(h->rtnl_handle, RTM_GETLINK) < 0) + return -1; + + return nlif_catch_multi(h); +} + +/** + * nlif_fd - get file descriptor for the netlink socket + * + * \param h pointer to nlif_handle created by nlif_open() + * \return The fd or -1 if there's an error + */ +int nlif_fd(struct nlif_handle *h) +{ + assert(h != NULL); + + if (h->rtnl_handle) + return h->rtnl_handle->rtnl_fd; + + return -1; +} + +/** + * @} + */