diff options
Diffstat (limited to 'flow.c')
| -rw-r--r-- | flow.c | 77 |
1 files changed, 75 insertions, 2 deletions
@@ -35,6 +35,46 @@ static_assert(ARRAY_SIZE(flow_proto) == FLOW_NUM_TYPES, /* Global Flow Table */ /** + * DOC: Theory of Operation - flow entry life cycle + * + * An individual flow table entry moves through these logical states, usually in + * this order. + * + * FREE - Part of the general pool of free flow table entries + * Operations: + * - flow_alloc() finds an entry and moves it to ALLOC state + * + * ALLOC - A tentatively allocated entry + * Operations: + * - flow_alloc_cancel() returns the entry to FREE state + * - FLOW_START() set the entry's type and moves to START state + * Caveats: + * - It's not safe to write fields in the flow entry + * - It's not safe to allocate further entries with flow_alloc() + * - It's not safe to return to the main epoll loop (use FLOW_START() + * to move to START state before doing so) + * - It's not safe to use flow_*() logging functions + * + * START - An entry being prepared by flow type specific code + * Operations: + * - Flow type specific fields may be accessed + * - flow_*() logging functions + * - flow_alloc_cancel() returns the entry to FREE state + * Caveats: + * - Returning to the main epoll loop or allocating another entry + * with flow_alloc() implicitly moves the entry to ACTIVE state. + * + * ACTIVE - An active flow entry managed by flow type specific code + * Operations: + * - Flow type specific fields may be accessed + * - flow_*() logging functions + * - Flow may be expired by returning 'true' from flow type specific + * deferred or timer handler. This will return it to FREE state. + * Caveats: + * - It's not safe to call flow_alloc_cancel() + */ + +/** * DOC: Theory of Operation - allocating and freeing flow entries * * Flows are entries in flowtab[]. We need to routinely scan the whole table to @@ -110,6 +150,39 @@ void flow_log_(const struct flow_common *f, int pri, const char *fmt, ...) } /** + * flow_start() - Set flow type for new flow and log + * @flow: Flow to set type for + * @type: Type for new flow + * @iniside: Which side initiated the new flow + * + * Return: @flow + * + * Should be called before setting any flow type specific fields in the flow + * table entry. + */ +union flow *flow_start(union flow *flow, enum flow_type type, + unsigned iniside) +{ + (void)iniside; + flow->f.type = type; + flow_dbg(flow, "START %s", flow_type_str[flow->f.type]); + return flow; +} + +/** + * flow_end() - Clear flow type for finished flow and log + * @flow: Flow to clear + */ +static void flow_end(union flow *flow) +{ + if (flow->f.type == FLOW_TYPE_NONE) + return; /* Nothing to do */ + + flow_dbg(flow, "END %s", flow_type_str[flow->f.type]); + flow->f.type = FLOW_TYPE_NONE; +} + +/** * flow_alloc() - Allocate a new flow * * Return: pointer to an unused flow entry, or NULL if the table is full @@ -157,7 +230,7 @@ void flow_alloc_cancel(union flow *flow) { ASSERT(flow_first_free > FLOW_IDX(flow)); - flow->f.type = FLOW_TYPE_NONE; + flow_end(flow); /* Put it back in a length 1 free cluster, don't attempt to fully * reverse flow_alloc()s steps. This will get folded together the next * time flow_defer_handler runs anyway() */ @@ -227,7 +300,7 @@ void flow_defer_handler(const struct ctx *c, const struct timespec *now) } if (closed) { - flow->f.type = FLOW_TYPE_NONE; + flow_end(flow); if (free_head) { /* Add slot to current free cluster */ |