83 lines
2.9 KiB
Diff
83 lines
2.9 KiB
Diff
From 5e0c290415b9d57077a86e70c8e6a058868334d3 Mon Sep 17 00:00:00 2001
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From: Stefan Hajnoczi <stefanha@redhat.com>
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Date: Wed, 15 Jul 2015 18:16:58 +0100
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Subject: [PATCH 1/7] rtl8139: avoid nested ifs in IP header parsing
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Transmit offload needs to parse packet headers. If header fields have
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unexpected values the offload processing is skipped.
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The code currently uses nested ifs because there is relatively little
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input validation. The next patches will add missing input validation
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and a goto label is more appropriate to avoid deep if statement nesting.
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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---
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hw/net/rtl8139.c | 41 ++++++++++++++++++++++-------------------
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1 file changed, 22 insertions(+), 19 deletions(-)
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diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c
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index 5f0197c..91ba33b 100644
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--- a/hw/net/rtl8139.c
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+++ b/hw/net/rtl8139.c
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@@ -2174,28 +2174,30 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s)
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size_t eth_payload_len = 0;
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int proto = be16_to_cpu(*(uint16_t *)(saved_buffer + 12));
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- if (proto == ETH_P_IP)
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+ if (proto != ETH_P_IP)
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{
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- DPRINTF("+++ C+ mode has IP packet\n");
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-
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- /* not aligned */
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- eth_payload_data = saved_buffer + ETH_HLEN;
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- eth_payload_len = saved_size - ETH_HLEN;
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-
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- ip = (ip_header*)eth_payload_data;
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-
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- if (IP_HEADER_VERSION(ip) != IP_HEADER_VERSION_4) {
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- DPRINTF("+++ C+ mode packet has bad IP version %d "
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- "expected %d\n", IP_HEADER_VERSION(ip),
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- IP_HEADER_VERSION_4);
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- ip = NULL;
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- } else {
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- hlen = IP_HEADER_LENGTH(ip);
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- ip_protocol = ip->ip_p;
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- ip_data_len = be16_to_cpu(ip->ip_len) - hlen;
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- }
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+ goto skip_offload;
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}
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+ DPRINTF("+++ C+ mode has IP packet\n");
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+
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+ /* not aligned */
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+ eth_payload_data = saved_buffer + ETH_HLEN;
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+ eth_payload_len = saved_size - ETH_HLEN;
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+
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+ ip = (ip_header*)eth_payload_data;
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+
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+ if (IP_HEADER_VERSION(ip) != IP_HEADER_VERSION_4) {
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+ DPRINTF("+++ C+ mode packet has bad IP version %d "
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+ "expected %d\n", IP_HEADER_VERSION(ip),
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+ IP_HEADER_VERSION_4);
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+ goto skip_offload;
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+ }
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+
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+ hlen = IP_HEADER_LENGTH(ip);
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+ ip_protocol = ip->ip_p;
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+ ip_data_len = be16_to_cpu(ip->ip_len) - hlen;
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+
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if (ip)
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{
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if (txdw0 & CP_TX_IPCS)
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@@ -2391,6 +2393,7 @@ static int rtl8139_cplus_transmit_one(RTL8139State *s)
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}
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}
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+skip_offload:
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/* update tally counter */
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++s->tally_counters.TxOk;
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--
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2.1.4
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