Date: Wed, 1 Nov 2023 09:30:35 GMT From: Michael Tuexen <tuexen@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: aa64a8f5c35c - main - udplite: fix checksum computation on the sender side Message-ID: <202311010930.3A19UZFg008306@gitrepo.freebsd.org>
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The branch main has been updated by tuexen: URL: https://cgit.FreeBSD.org/src/commit/?id=aa64a8f5c35c13b1c325f1a4597c987a37bec5da commit aa64a8f5c35c13b1c325f1a4597c987a37bec5da Author: Michael Tuexen <tuexen@FreeBSD.org> AuthorDate: 2023-11-01 09:24:56 +0000 Commit: Michael Tuexen <tuexen@FreeBSD.org> CommitDate: 2023-11-01 09:24:56 +0000 udplite: fix checksum computation on the sender side Don't fill the fields of the UDP/IP header not used for the checksum computation before performing the checksum computation. Reviewed by: glebius MFC after: 3 days Differential Revision: https://reviews.freebsd.org/D42275 --- sys/netinet/udp_usrreq.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) diff --git a/sys/netinet/udp_usrreq.c b/sys/netinet/udp_usrreq.c index cbda7f536262..a96ec22c5992 100644 --- a/sys/netinet/udp_usrreq.c +++ b/sys/netinet/udp_usrreq.c @@ -1330,8 +1330,12 @@ udp_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *addr, * into network format. */ ui = mtod(m, struct udpiphdr *); - bzero(ui->ui_x1, sizeof(ui->ui_x1)); /* XXX still needed? */ - ui->ui_v = IPVERSION << 4; + /* + * Filling only those fields of udpiphdr that participate in the + * checksum calculation. The rest must be zeroed and will be filled + * later. + */ + bzero(ui->ui_x1, sizeof(ui->ui_x1)); ui->ui_pr = pr; ui->ui_src = laddr; ui->ui_dst = faddr; @@ -1356,16 +1360,6 @@ udp_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *addr, cscov_partial = (cscov == 0) ? 0 : 1; } - /* - * Set the Don't Fragment bit in the IP header. - */ - if (inp->inp_flags & INP_DONTFRAG) { - struct ip *ip; - - ip = (struct ip *)&ui->ui_i; - ip->ip_off |= htons(IP_DF); - } - if (inp->inp_socket->so_options & SO_DONTROUTE) ipflags |= IP_ROUTETOIF; if (inp->inp_socket->so_options & SO_BROADCAST) @@ -1399,9 +1393,16 @@ udp_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *addr, m->m_pkthdr.csum_flags = CSUM_UDP; m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum); } + /* + * After finishing the checksum computation, fill the remaining fields + * of udpiphdr. + */ + ((struct ip *)ui)->ip_v = IPVERSION; + ((struct ip *)ui)->ip_tos = tos; ((struct ip *)ui)->ip_len = htons(sizeof(struct udpiphdr) + len); - ((struct ip *)ui)->ip_ttl = inp->inp_ip_ttl; /* XXX */ - ((struct ip *)ui)->ip_tos = tos; /* XXX */ + if (inp->inp_flags & INP_DONTFRAG) + ((struct ip *)ui)->ip_off |= htons(IP_DF); + ((struct ip *)ui)->ip_ttl = inp->inp_ip_ttl; UDPSTAT_INC(udps_opackets); /*
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