From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=none (p=none dis=none) header.from=gibson.dropbear.id.au Authentication-Results: passt.top; dkim=pass (2048-bit key; secure) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.a=rsa-sha256 header.s=202502 header.b=DvqpFzei; dkim-atps=neutral Received: from mail.ozlabs.org (mail.ozlabs.org [IPv6:2404:9400:2221:ea00::3]) by passt.top (Postfix) with ESMTPS id C77935A077F for ; Mon, 17 Mar 2025 11:02:26 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=202502; t=1742205731; bh=fKOCJQpCoc4K9YSboQclJcRod2xCUlOB2aPzn64AUP4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DvqpFzeirzoRL17a47llvM6eGl6fz7XbkEn8JN6o4ey5lhsRFMK1LgtVvuffj8L2/ 8sQdB/tnjQrhnau2hwerHPSzopEsMSYE3PaSTngo+9ajdlHCvpVUA3ELuG/GWN5e3H fIm1e2rkDPeVXr27SsxxJdvPj+pEDuAMSTjROxDc594AU1W6L2EZdfkp+t4XskAZKe Bt/CBQUSnYz9NlHVg/fXEIvaX1Lr4+I02aP73e0B4G+jf8V4N49B9WYxfXDN+B8mf6 Qs15lT3WDO3CoDnyV12fp5AqrJnfoT+T4AE28PXd+CBJqW2LK3BCsUpb0DcmFEtWeR LbTyw5IEVsx9Q== Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4ZGVrM6LNqz4xCy; Mon, 17 Mar 2025 21:02:11 +1100 (AEDT) From: David Gibson To: passt-dev@passt.top, Stefano Brivio Subject: [PATCH v2 08/11] packet: Rework packet_get() versus packet_get_try() Date: Mon, 17 Mar 2025 20:24:21 +1100 Message-ID: <20250317092424.1461719-9-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250317092424.1461719-1-david@gibson.dropbear.id.au> References: <20250317092424.1461719-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID-Hash: 35Q42TZKKY7HLG2VP3PJA2FHLWPP4GSS X-Message-ID-Hash: 35Q42TZKKY7HLG2VP3PJA2FHLWPP4GSS X-MailFrom: dgibson@gandalf.ozlabs.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: David Gibson X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: Most failures of packet_get() indicate a serious problem, and log messages accordingly. However, a few callers expect failures here, because they're probing for a certain range which might or might not be in a packet. They use packet_get_try() which passes a NULL func to packet_get_do() to suppress the logging which is unwanted in this case. However, this doesn't just suppress the log when packet_get_do() finds the requested region isn't in the packet. It suppresses logging for all other errors too, which do indicate serious problems, even for the callers of packet_get_try(). Worse it will pass the NULL func on to packet_check_range() which doesn't expect it, meaning we'll get unhelpful messages from there if there is a failure. Fix this by making packet_get_try_do() the primary function which doesn't log for the case of a range outside the packet. packet_get_do() becomes a trivial wrapper around that which logs a message if packet_get_try_do() returns NULL. Signed-off-by: David Gibson --- packet.c | 51 +++++++++++++++++++++++++++++++++++---------------- packet.h | 8 +++++--- 2 files changed, 40 insertions(+), 19 deletions(-) diff --git a/packet.c b/packet.c index 7cbe95da..b3e8c79e 100644 --- a/packet.c +++ b/packet.c @@ -89,7 +89,7 @@ bool pool_full(const struct pool *p) * @p: Existing pool * @len: Length of new descriptor * @start: Start of data - * @func: For tracing: name of calling function, NULL means no trace() + * @func: For tracing: name of calling function * @line: For tracing: caller line of function call */ void packet_add_do(struct pool *p, size_t len, const char *start, @@ -113,39 +113,31 @@ void packet_add_do(struct pool *p, size_t len, const char *start, } /** - * packet_get_do() - Get data range from packet descriptor from given pool + * packet_get_try_do() - Get data range from packet descriptor from given pool * @p: Packet pool * @idx: Index of packet descriptor in pool * @offset: Offset of data range in packet descriptor * @len: Length of desired data range * @left: Length of available data after range, set on return, can be NULL - * @func: For tracing: name of calling function, NULL means no trace() + * @func: For tracing: name of calling function * @line: For tracing: caller line of function call * * Return: pointer to start of data range, NULL on invalid range or descriptor */ -void *packet_get_do(const struct pool *p, size_t idx, size_t offset, - size_t len, size_t *left, const char *func, int line) +void *packet_get_try_do(const struct pool *p, size_t idx, size_t offset, + size_t len, size_t *left, const char *func, int line) { char *ptr; if (idx >= p->size || idx >= p->count) { - if (func) { - trace("packet %zu from pool size: %zu, count: %zu, " - "%s:%i", idx, p->size, p->count, func, line); - } + trace("packet %zu from pool size: %zu, count: %zu, %s:%i", + idx, p->size, p->count, func, line); return NULL; } if (offset > p->pkt[idx].iov_len || - len > (p->pkt[idx].iov_len - offset)) { - if (func) { - trace("data length %zu, offset %zu from length %zu, " - "%s:%i", len, offset, p->pkt[idx].iov_len, - func, line); - } + len > (p->pkt[idx].iov_len - offset)) return NULL; - } ptr = (char *)p->pkt[idx].iov_base + offset; @@ -158,6 +150,33 @@ void *packet_get_do(const struct pool *p, size_t idx, size_t offset, return ptr; } +/** + * packet_get_do() - Get data range from packet descriptor from given pool + * @p: Packet pool + * @idx: Index of packet descriptor in pool + * @offset: Offset of data range in packet descriptor + * @len: Length of desired data range + * @left: Length of available data after range, set on return, can be NULL + * @func: For tracing: name of calling function + * @line: For tracing: caller line of function call + * + * Return: as packet_get_try_do() but log a trace message when returning NULL + */ +void *packet_get_do(const struct pool *p, const size_t idx, + size_t offset, size_t len, size_t *left, + const char *func, int line) +{ + void *r = packet_get_try_do(p, idx, offset, len, left, func, line); + + if (!r) { + trace("missing packet data length %zu, offset %zu from " + "length %zu, %s:%i", + len, offset, p->pkt[idx].iov_len, func, line); + } + + return r; +} + /** * pool_flush() - Flush a packet pool * @p: Pointer to packet pool diff --git a/packet.h b/packet.h index 9061dad7..c94780a5 100644 --- a/packet.h +++ b/packet.h @@ -32,6 +32,9 @@ struct pool { int vu_packet_check_range(void *buf, const char *ptr, size_t len); void packet_add_do(struct pool *p, size_t len, const char *start, const char *func, int line); +void *packet_get_try_do(const struct pool *p, const size_t idx, + size_t offset, size_t len, size_t *left, + const char *func, int line); void *packet_get_do(const struct pool *p, const size_t idx, size_t offset, size_t len, size_t *left, const char *func, int line); @@ -41,12 +44,11 @@ void pool_flush(struct pool *p); #define packet_add(p, len, start) \ packet_add_do(p, len, start, __func__, __LINE__) +#define packet_get_try(p, idx, offset, len, left) \ + packet_get_try_do(p, idx, offset, len, left, __func__, __LINE__) #define packet_get(p, idx, offset, len, left) \ packet_get_do(p, idx, offset, len, left, __func__, __LINE__) -#define packet_get_try(p, idx, offset, len, left) \ - packet_get_do(p, idx, offset, len, left, NULL, 0) - #define PACKET_POOL_DECL(_name, _size, _buf) \ struct _name ## _t { \ char *buf; \ -- 2.48.1