diff options
| -rw-r--r-- | share/man/man4/ip.4 | 28 | ||||
| -rw-r--r-- | sys/netinet/in.h | 1 | ||||
| -rw-r--r-- | sys/netinet/udp_usrreq.c | 66 |
3 files changed, 91 insertions, 4 deletions
diff --git a/share/man/man4/ip.4 b/share/man/man4/ip.4 index 69b0f2a..cae7061 100644 --- a/share/man/man4/ip.4 +++ b/share/man/man4/ip.4 @@ -136,6 +136,34 @@ cmsg_level = IPPROTO_IP cmsg_type = IP_RECVDSTADDR .Ed .Pp +The source address to be used for outgoing +.Tn UDP +datagrams on a socket that is not bound to a specific +.Tn IP +address can be specified as ancillary data with a type code of +.Dv IP_SENDSRCADDR . +The msg_control field in the msghdr structure should point to a buffer +that contains a cmsghdr structure followed by the +.Tn IP +address. +The cmsghdr fields should have the following values: +.Bd -literal +cmsg_len = sizeof(struct in_addr) +cmsg_level = IPPROTO_IP +cmsg_type = IP_SENDSRCADDR +.Ed +.Pp +For convenience, +.Dv IP_SENDSRCADDR +is defined to have the same value as +.Dv IP_RECVDSTADDR , +so the +.Dv IP_RECVDSTADDR +control message from +.Xr recvmsg 2 +can be used directly as a control message for +.Xr sendmsg 2 . +.Pp .Dv IP_PORTRANGE may be used to set the port range used for selecting a local port number on a socket with an unspecified (zero) port number. diff --git a/sys/netinet/in.h b/sys/netinet/in.h index 09fb134..09fd395 100644 --- a/sys/netinet/in.h +++ b/sys/netinet/in.h @@ -366,6 +366,7 @@ __END_DECLS #define IP_RECVOPTS 5 /* bool; receive all IP opts w/dgram */ #define IP_RECVRETOPTS 6 /* bool; receive IP opts for response */ #define IP_RECVDSTADDR 7 /* bool; receive IP dst addr w/dgram */ +#define IP_SENDSRCADDR IP_RECVDSTADDR /* cmsg_type to set src addr */ #define IP_RETOPTS 8 /* ip_opts; set/get IP options */ #define IP_MULTICAST_IF 9 /* u_char; set/get IP multicast i/f */ #define IP_MULTICAST_TTL 10 /* u_char; set/get IP multicast ttl */ diff --git a/sys/netinet/udp_usrreq.c b/sys/netinet/udp_usrreq.c index 263a92e..437ee4e 100644 --- a/sys/netinet/udp_usrreq.c +++ b/sys/netinet/udp_usrreq.c @@ -689,7 +689,8 @@ udp_output(inp, m, addr, control, td) register struct udpiphdr *ui; register int len = m->m_pkthdr.len; struct in_addr faddr, laddr; - struct sockaddr_in *sin; + struct cmsghdr *cm; + struct sockaddr_in *sin, src; int error = 0; u_short fport, lport; @@ -697,16 +698,73 @@ udp_output(inp, m, addr, control, td) mac_create_mbuf_from_socket(inp->inp_socket, m); #endif - if (control) - m_freem(control); /* XXX */ - if (len + sizeof(struct udpiphdr) > IP_MAXPACKET) { error = EMSGSIZE; + if (control) + m_freem(control); goto release; } + src.sin_addr.s_addr = INADDR_ANY; + if (control != NULL) { + /* + * XXX: Currently, we assume all the optional information + * is stored in a single mbuf. + */ + if (control->m_next) { + error = EINVAL; + m_freem(control); + goto release; + } + for (; control->m_len > 0; + control->m_data += CMSG_ALIGN(cm->cmsg_len), + control->m_len -= CMSG_ALIGN(cm->cmsg_len)) { + cm = mtod(control, struct cmsghdr *); + if (control->m_len < sizeof(*cm) || cm->cmsg_len == 0 || + cm->cmsg_len > control->m_len) { + error = EINVAL; + break; + } + if (cm->cmsg_level != IPPROTO_IP) + continue; + + switch (cm->cmsg_type) { + case IP_SENDSRCADDR: + if (cm->cmsg_len != + CMSG_LEN(sizeof(struct in_addr))) { + error = EINVAL; + break; + } + bzero(&src, sizeof(src)); + src.sin_family = AF_INET; + src.sin_len = sizeof(src); + src.sin_port = inp->inp_lport; + src.sin_addr = *(struct in_addr *)CMSG_DATA(cm); + break; + default: + error = ENOPROTOOPT; + break; + } + if (error) + break; + } + m_freem(control); + } + if (error) + goto release; laddr = inp->inp_laddr; lport = inp->inp_lport; + if (src.sin_addr.s_addr != INADDR_ANY) { + if (lport == 0) { + error = EINVAL; + goto release; + } + error = in_pcbbind_setup(inp, (struct sockaddr *)&src, + &laddr.s_addr, &lport, td); + if (error) + goto release; + } + if (addr) { sin = (struct sockaddr_in *)addr; if (td && jailed(td->td_ucred)) |
