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| author | Michael Tuexen <tuexen@FreeBSD.org> | 2023-11-01 09:24:56 +0000 |
|---|---|---|
| committer | Michael Tuexen <tuexen@FreeBSD.org> | 2024-01-12 17:22:20 +0000 |
| commit | 15eda0e9027d39d4e38e23a31752b1e02e2d2d6c (patch) | |
| tree | fba3243ba3707fc9c9d0e4edae33363486d947f0 | |
| parent | c85e01d0bfddcd23123a8b69d7a92cda55f2e526 (diff) | |
| download | src-15eda0e9027d39d4e38e23a31752b1e02e2d2d6c.tar.gz src-15eda0e9027d39d4e38e23a31752b1e02e2d2d6c.zip | |
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
Differential Revision: https://reviews.freebsd.org/D42275
(cherry picked from commit aa64a8f5c35c13b1c325f1a4597c987a37bec5da)
| -rw-r--r-- | sys/netinet/udp_usrreq.c | 29 |
1 files changed, 15 insertions, 14 deletions
diff --git a/sys/netinet/udp_usrreq.c b/sys/netinet/udp_usrreq.c index a476b0d8251a..ea9ff161e429 100644 --- a/sys/netinet/udp_usrreq.c +++ b/sys/netinet/udp_usrreq.c @@ -1408,8 +1408,12 @@ udp_output(struct inpcb *inp, 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; @@ -1434,16 +1438,6 @@ udp_output(struct inpcb *inp, 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) @@ -1477,9 +1471,16 @@ udp_output(struct inpcb *inp, 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); /* |