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5329647dad
Since BIG TCP for UDP tunnels will start using len=0 in the UDP header as an indicator of a GSO packet bigger than 65535 bytes, this commit introduces the following getter and setters to use tree-wide, in order to explicitly mark places where len=0 may be expected, and handle them properly: 1. udp_set_len() sets uh->len to its real value if it's not bigger than 65535, and to 0 otherwise: to be used in GSO context with aggregated packets. 2. udp_set_len_short() is to be used when the length is known to fit 16 bits. It WARNs when the caller tries to assign a bigger value if CONFIG_DEBUG_NET=y. 3. udp_get_len_short() returns len in host byte order: to be used on the RX side to deal with non-aggregated packets, or to access the raw value of the len field. 4. udp_get_len() decodes uh->len set by udp_set_len(). It checks whether the packet is GSO to guard from malformed packets. At the moment udp_set_len() is not used, a following commit will start using it after enabling len>65535 for GSO. Raw uh->len (in network byte order) is still accessed in a few places for checksum calculation purposes, and to decode len=0 in udpv6_rcv for jumbograms. udp_rcv and udpv6_rcv will be addressed by the commit that starts using udp_set_len() to set UDP len=0 for BIG TCP packets in UDP tunnels. Signed-off-by: Alice Mikityanska <alice@isovalent.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Acked-by: Jason A. Donenfeld <Jason@zx2c4.com> Link: https://patch.msgid.link/20260710134242.216538-2-alice.kernel@fastmail.im Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
86 lines
2.3 KiB
C
86 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* This tests the blackhole_dev that is created during the
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* net subsystem initialization. The test this module performs is
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* by injecting an skb into the stack with skb->dev as the
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* blackhole_dev and expects kernel to behave in a sane manner
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* (in other words, *not crash*)!
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*
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* Copyright (c) 2018, Mahesh Bandewar <maheshb@google.com>
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*/
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#include <kunit/test.h>
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/netdevice.h>
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#include <linux/udp.h>
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#include <linux/ipv6.h>
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#include <net/dst.h>
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#define SKB_SIZE 256
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#define HEAD_SIZE (14+40+8) /* Ether + IPv6 + UDP */
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#define TAIL_SIZE 32 /* random tail-room */
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#define UDP_PORT 1234
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static void test_blackholedev(struct kunit *test)
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{
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struct ipv6hdr *ip6h;
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struct sk_buff *skb;
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struct udphdr *uh;
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int data_len;
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skb = alloc_skb(SKB_SIZE, GFP_KERNEL);
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KUNIT_ASSERT_NOT_NULL(test, skb);
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/* Reserve head-room for the headers */
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skb_reserve(skb, HEAD_SIZE);
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/* Add data to the skb */
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data_len = SKB_SIZE - (HEAD_SIZE + TAIL_SIZE);
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memset(__skb_put(skb, data_len), 0xf, data_len);
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/* Add protocol data */
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/* (Transport) UDP */
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uh = (struct udphdr *)skb_push(skb, sizeof(struct udphdr));
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skb_set_transport_header(skb, 0);
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uh->source = uh->dest = htons(UDP_PORT);
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udp_set_len_short(uh, data_len);
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uh->check = 0;
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/* (Network) IPv6 */
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ip6h = (struct ipv6hdr *)skb_push(skb, sizeof(struct ipv6hdr));
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skb_set_network_header(skb, 0);
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ip6h->hop_limit = 32;
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ip6h->payload_len = htons(data_len + sizeof(struct udphdr));
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ip6h->nexthdr = IPPROTO_UDP;
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ip6h->saddr = in6addr_loopback;
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ip6h->daddr = in6addr_loopback;
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/* Ether */
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skb_push(skb, sizeof(struct ethhdr));
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skb_set_mac_header(skb, 0);
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skb->protocol = htons(ETH_P_IPV6);
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skb->pkt_type = PACKET_HOST;
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skb->dev = blackhole_netdev;
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/* Now attempt to send the packet */
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KUNIT_EXPECT_EQ(test, dev_queue_xmit(skb), NET_XMIT_SUCCESS);
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}
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static struct kunit_case blackholedev_cases[] = {
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KUNIT_CASE(test_blackholedev),
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{},
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};
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static struct kunit_suite blackholedev_suite = {
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.name = "blackholedev",
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.test_cases = blackholedev_cases,
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};
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kunit_test_suite(blackholedev_suite);
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MODULE_AUTHOR("Mahesh Bandewar <maheshb@google.com>");
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MODULE_DESCRIPTION("module test of the blackhole_dev");
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MODULE_LICENSE("GPL");
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