From ca38be0141d17cbdd419fc49fb028a96612aa3b5 Mon Sep 17 00:00:00 2001 From: Laurent Vivier Date: Tue, 2 Sep 2025 09:52:53 +0200 Subject: packet: Add support for multi-vector packets The packet pool was previously limited to handling packets contained within a single buffer. This patch extends the packet pool to support iovec array, allowing a single logical packet to be composed of multiple iovec. To accommodate this, the storage format within the pool is modified. For a multi-vector packet, a header entry is now stored first with iov_base = NULL and iov_len holding the number of subsequent vectors. The actual data vectors are then stored in the following pool slots. The packet_add_do() and packet_get_do() functions are updated to manage this new format for storing and retrieving packets. The pool_full() check is also adjusted to ensure there is enough space for all vectors of a new packet before adding it. Signed-off-by: Laurent Vivier Reviewed-by: David Gibson Signed-off-by: Stefano Brivio --- packet.c | 54 ++++++++++++++++++++++++++++++++++++------------------ packet.h | 2 +- tap.c | 4 ++-- 3 files changed, 39 insertions(+), 21 deletions(-) diff --git a/packet.c b/packet.c index 27693c5..890561b 100644 --- a/packet.c +++ b/packet.c @@ -91,14 +91,17 @@ static int packet_check_range(const struct pool *p, const char *ptr, size_t len, return 0; } /** - * pool_full() - Is a packet pool full? + * pool_can_fit() - Can a new packet fit in the pool? * @p: Pointer to packet pool + * @data: check data can fit in the pool * - * Return: true if the pool is full, false if more packets can be added + * Return: true if @data can be added, false otherwise */ -bool pool_full(const struct pool *p) +bool pool_can_fit(const struct pool *p, struct iov_tail *data) { - return p->count >= p->size; + iov_tail_prune(data); + + return p->count + data->cnt + (data->cnt > 1) <= p->size; } /** @@ -111,11 +114,9 @@ bool pool_full(const struct pool *p) void packet_add_do(struct pool *p, struct iov_tail *data, const char *func, int line) { - size_t idx = p->count; - const char *start; - size_t len; + size_t idx = p->count, i, offset; - if (pool_full(p)) { + if (!pool_can_fit(p, data)) { debug("add packet index %zu to pool with size %zu, %s:%i", idx, p->size, func, line); return; @@ -124,18 +125,30 @@ void packet_add_do(struct pool *p, struct iov_tail *data, if (!iov_tail_prune(data)) return; - ASSERT(data->cnt == 1); /* we don't support iovec */ + if (data->cnt > 1) { + p->pkt[idx].iov_base = NULL; + p->pkt[idx].iov_len = data->cnt; + idx++; + } - len = data->iov[0].iov_len - data->off; - start = (char *)data->iov[0].iov_base + data->off; + offset = data->off; + for (i = 0; i < data->cnt; i++) { + const char *start; + size_t len; - if (packet_check_range(p, start, len, func, line)) - return; + len = data->iov[i].iov_len - offset; + start = (char *)data->iov[i].iov_base + offset; + offset = 0; - p->pkt[idx].iov_base = (void *)start; - p->pkt[idx].iov_len = len; + if (packet_check_range(p, start, len, func, line)) + return; - p->count++; + p->pkt[idx].iov_base = (void *)start; + p->pkt[idx].iov_len = len; + idx++; + } + + p->count = idx; } /** @@ -165,9 +178,14 @@ bool packet_get_do(const struct pool *p, size_t idx, return false; } - data->cnt = 1; + if (p->pkt[idx].iov_base) { + data->cnt = 1; + data->iov = &p->pkt[idx]; + } else { + data->cnt = p->pkt[idx].iov_len; + data->iov = &p->pkt[idx + 1]; + } data->off = 0; - data->iov = &p->pkt[idx]; for (i = 0; i < data->cnt; i++) { ASSERT_WITH_MSG(!packet_check_range(p, data->iov[i].iov_base, diff --git a/packet.h b/packet.h index e51cbd1..ba8d5c2 100644 --- a/packet.h +++ b/packet.h @@ -37,7 +37,7 @@ void packet_add_do(struct pool *p, struct iov_tail *data, const char *func, int line); bool packet_get_do(const struct pool *p, const size_t idx, struct iov_tail *data, const char *func, int line); -bool pool_full(const struct pool *p); +bool pool_can_fit(const struct pool *p, struct iov_tail *data); void pool_flush(struct pool *p); #define packet_add(p, data) \ diff --git a/tap.c b/tap.c index 5e0173b..7ba6399 100644 --- a/tap.c +++ b/tap.c @@ -1103,14 +1103,14 @@ void tap_add_packet(struct ctx *c, struct iov_tail *data, switch (ntohs(eh->h_proto)) { case ETH_P_ARP: case ETH_P_IP: - if (pool_full(pool_tap4)) { + if (!pool_can_fit(pool_tap4, data)) { tap4_handler(c, pool_tap4, now); pool_flush(pool_tap4); } packet_add(pool_tap4, data); break; case ETH_P_IPV6: - if (pool_full(pool_tap6)) { + if (!pool_can_fit(pool_tap6, data)) { tap6_handler(c, pool_tap6, now); pool_flush(pool_tap6); } -- cgit v1.2.3