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94eb0858c2
There is a simple universal IO loop, taking care of events, timers and sockets. Primarily, one instance of a protocol should use exactly one IO loop to do all its work, as is now done in BFD. Contrary to previous versions, the loop is now launched and cleaned by the nest/proto.c code, allowing for a protocol to just request its own loop by setting the loop's lock order in config higher than the_bird. It is not supported nor checked if any protocol changed the requested lock order in reconfigure. No protocol should do it at all.
102 lines
2.9 KiB
C
102 lines
2.9 KiB
C
/*
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* BIRD Library -- Linked Lists
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*
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* (c) 1998 Martin Mares <mj@ucw.cz>
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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#ifndef _BIRD_LISTS_H_
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#define _BIRD_LISTS_H_
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/*
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* I admit the list structure is very tricky and also somewhat awkward,
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* but it's both efficient and easy to manipulate once one understands the
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* basic trick: The list head always contains two synthetic nodes which are
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* always present in the list: the head and the tail. But as the `next'
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* entry of the tail and the `prev' entry of the head are both NULL, the
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* nodes can overlap each other:
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*
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* head head_node.next
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* null head_node.prev tail_node.next
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* tail tail_node.prev
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*/
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typedef struct node {
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struct node *next, *prev;
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} node;
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typedef union list { /* In fact two overlayed nodes */
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struct { /* Head node */
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struct node head_node;
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void *head_padding;
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};
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struct { /* Tail node */
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void *tail_padding;
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struct node tail_node;
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};
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struct { /* Split to separate pointers */
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struct node *head;
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struct node *null;
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struct node *tail;
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};
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} list;
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#define NODE (node *)
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#define HEAD(list) ((void *)((list).head))
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#define TAIL(list) ((void *)((list).tail))
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#define NODE_NEXT(n) ((void *)((NODE (n))->next))
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#define NODE_VALID(n) ((NODE (n))->next)
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#define WALK_LIST(n,list) for(n=HEAD(list); NODE_VALID(n); n=NODE_NEXT(n))
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#define WALK_LIST2(n,nn,list,pos) \
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for(nn=(list).head; NODE_VALID(nn) && (n=SKIP_BACK(typeof(*n),pos,nn)); nn=nn->next)
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#define WALK_LIST_DELSAFE(n,nxt,list) \
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for(n=HEAD(list); nxt=NODE_NEXT(n); n=(void *) nxt)
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#define WALK_LIST2_DELSAFE(n,nn,nxt,list,pos) \
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for(nn=HEAD(list); (nxt=nn->next) && (n=SKIP_BACK(typeof(*n),pos,nn)); nn=nxt)
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/* WALK_LIST_FIRST supposes that called code removes each processed node */
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#define WALK_LIST_FIRST(n,list) \
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while(n=HEAD(list), (NODE (n))->next)
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#define WALK_LIST_FIRST2(n,pos,list) \
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while(n=SKIP_BACK(typeof(*n),pos,HEAD(list)), (n)->pos.next)
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#define WALK_LIST_BACKWARDS(n,list) for(n=TAIL(list);(NODE (n))->prev; \
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n=(void *)((NODE (n))->prev))
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#define WALK_LIST_BACKWARDS_DELSAFE(n,prv,list) \
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for(n=TAIL(list); prv=(void *)((NODE (n))->prev); n=(void *) prv)
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#define EMPTY_LIST(list) (!(list).head->next)
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static inline _Bool
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enlisted(node *n)
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{
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switch ((!!n->next) + (!!n->prev))
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{
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case 0: return 0;
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case 2: return 1;
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case 1: bug("Garbled event list node");
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}
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bug("Maths is broken. And you should see a new heaven and a new earth: for the first heaven and the first earth had been passed away.");
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}
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#ifndef _BIRD_LISTS_C_
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#define LIST_INLINE static inline
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#include "lib/lists.c"
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#undef LIST_INLINE
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#else /* _BIRD_LISTS_C_ */
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#define LIST_INLINE
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void add_tail(list *, node *);
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void add_head(list *, node *);
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void self_link(node *);
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void rem_node(node *);
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void add_tail_list(list *, list *);
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void init_list(list *);
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void insert_node(node *, node *);
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uint list_length(list *);
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#endif
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#endif
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