On Tue, May 1, 2018 at 9:59 PM, Neil Horman <nhorman@xxxxxxxxxxxxx> wrote:
> On Tue, May 01, 2018 at 06:24:07PM +0800, Xin Long wrote:
>> This patch is to implement sctp_sendv and sctp_recvv defined in
>> rfc6458#section-9.12 and 9.13. They provide an extensible way
>> for users to send or receive messages from a SCTP socket.
>>
>> Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
>> ---
>> src/include/netinet/sctp.h | 43 ++++++++++++
>> src/lib/Versions.map | 2 +
>> src/lib/recvmsg.c | 88 +++++++++++++++++++++++++
>> src/lib/sendmsg.c | 161 +++++++++++++++++++++++++++++++++++++++++++++
>> 4 files changed, 294 insertions(+)
>>
>> diff --git a/src/include/netinet/sctp.h b/src/include/netinet/sctp.h
>> index a0cd14c..701f091 100644
>> --- a/src/include/netinet/sctp.h
>> +++ b/src/include/netinet/sctp.h
>> @@ -122,6 +122,49 @@ int sctp_recvmsg(int s, void *msg, size_t len, struct sockaddr *from,
>> /* Return the address length for an address family. */
>> int sctp_getaddrlen(sa_family_t family);
>>
>> +
>> +/* sendv infotype */
>> +enum {
>> + SCTP_SENDV_NOINFO,
>> + SCTP_SENDV_SNDINFO,
>> + SCTP_SENDV_PRINFO,
>> + SCTP_SENDV_AUTHINFO,
>> + SCTP_SENDV_SPA
>> +};
>> +
>> +/* sendv_flags */
>> +#define SCTP_SEND_SNDINFO_VALID 0x1
>> +#define SCTP_SEND_PRINFO_VALID 0x2
>> +#define SCTP_SEND_AUTHINFO_VALID 0x4
>> +
>> +struct sctp_sendv_spa {
>> + uint32_t sendv_flags;
>> + struct sctp_sndinfo sendv_sndinfo;
>> + struct sctp_prinfo sendv_prinfo;
>> + struct sctp_authinfo sendv_authinfo;
>> +};
>> +
>> +int sctp_sendv(int s, const struct iovec *iov, int iovcnt,
>> + struct sockaddr *addrs, int addrcnt, void *info,
>> + socklen_t infolen, unsigned int infotype, int flags);
>> +
>> +/* recvv infotype */
>> +enum {
>> + SCTP_RECVV_NOINFO,
>> + SCTP_RECVV_RCVINFO,
>> + SCTP_RECVV_NXTINFO,
>> + SCTP_RECVV_RN
>> +};
>> +
>> +struct sctp_recvv_rn {
>> + struct sctp_rcvinfo recvv_rcvinfo;
>> + struct sctp_nxtinfo recvv_nxtinfo;
>> +};
>> +
>> +int sctp_recvv(int s, const struct iovec *iov, int iovlen,
>> + struct sockaddr *from, socklen_t *fromlen, void *info,
>> + socklen_t *infolen, unsigned int *infotype, int *flags);
>> +
>> #ifdef __cplusplus
>> }
>> #endif
>> diff --git a/src/lib/Versions.map b/src/lib/Versions.map
>> index a3c5561..7faad5d 100644
>> --- a/src/lib/Versions.map
>> +++ b/src/lib/Versions.map
>> @@ -10,7 +10,9 @@ VERS_1 {
>> sctp_opt_info;
>> sctp_peeloff;
>> sctp_recvmsg;
>> + sctp_recvv;
>> sctp_sendmsg;
>> + sctp_sendv;
>> sctp_send;
>>
>> local:
>> diff --git a/src/lib/recvmsg.c b/src/lib/recvmsg.c
>> index 4575788..7c1dcad 100644
>> --- a/src/lib/recvmsg.c
>> +++ b/src/lib/recvmsg.c
>> @@ -99,3 +99,91 @@ int sctp_recvmsg(int s, void *msg, size_t len, struct sockaddr *from,
>>
>> return (error);
>> }
>> +
>> +int sctp_recvv(int s, const struct iovec *iov, int iovlen,
>> + struct sockaddr *from, socklen_t *fromlen, void *info,
>> + socklen_t *infolen, unsigned int *infotype, int *flags)
>> +{
>> + char incmsg[CMSG_SPACE(sizeof(struct sctp_rcvinfo) +
>> + sizeof(struct sctp_nxtinfo))];
>> + int error, len, _infolen;
>> + struct cmsghdr *cmsg;
>> + struct msghdr inmsg;
>> +
>> + memset(&inmsg, 0, sizeof(inmsg));
>> +
>> + /* set from and iov */
>> + inmsg.msg_name = from;
>> + inmsg.msg_namelen = fromlen ? *fromlen : 0;
>> + inmsg.msg_iov = (struct iovec *)iov;
>> + inmsg.msg_iovlen = iovlen;
>> + inmsg.msg_control = incmsg;
>> + inmsg.msg_controllen = sizeof(incmsg);
>> +
>> + error = recvmsg(s, &inmsg, flags ? *flags : 0);
>> + if (error < 0)
>> + return error;
>> +
>> + /* set fromlen, frags */
>> + if (fromlen)
>> + *fromlen = inmsg.msg_namelen;
>> +
>> + if (flags)
>> + *flags = inmsg.msg_flags;
>> +
>> + if (!info || !infotype || !infolen)
>> + return error;
>> +
>> + *infotype = SCTP_RECVV_NOINFO;
>> + _infolen = *infolen;
>> +
>> + /* set info and infotype */
>> + for (cmsg = CMSG_FIRSTHDR(&inmsg); cmsg != NULL;
>> + cmsg = CMSG_NXTHDR(&inmsg, cmsg)) {
>> + if (cmsg->cmsg_level != IPPROTO_SCTP)
>> + continue;
>> +
>> + if (cmsg->cmsg_type == SCTP_RCVINFO) {
>> + len = sizeof(struct sctp_rcvinfo);
>> + if (*infotype == SCTP_RECVV_NOINFO) {
>> + if (_infolen < len)
>> + break;
>> + memcpy(info, CMSG_DATA(cmsg), len);
>> + *infotype = SCTP_RECVV_RCVINFO;
>> + *infolen = len;
>> + } else if (*infotype == SCTP_RECVV_NXTINFO) {
>> + if (_infolen < len +
>> + sizeof(struct sctp_nxtinfo))
>> + break;
>> + memcpy(info + len, info,
>> + sizeof(struct sctp_nxtinfo));
>> + memcpy(info, CMSG_DATA(cmsg), len);
>> + *infotype = SCTP_RECVV_RN;
>> + *infolen = len + sizeof(struct sctp_nxtinfo);
>> + } else {
>> + break;
>> + }
>> + } else if (cmsg->cmsg_type == SCTP_NXTINFO) {
>> + len = sizeof(struct sctp_nxtinfo);
>> + if (*infotype == SCTP_RECVV_NOINFO) {
>> + if (_infolen < len)
>> + break;
>> + memcpy(info, CMSG_DATA(cmsg), len);
>> + *infotype = SCTP_RECVV_NXTINFO;
>> + *infolen = len;
>> + } else if (*infotype == SCTP_RECVV_RCVINFO) {
>> + if (_infolen < len +
>> + sizeof(struct sctp_rcvinfo))
>> + break;
>> + memcpy(info + sizeof(struct sctp_rcvinfo),
>> + CMSG_DATA(cmsg), len);
>> + *infotype = SCTP_RECVV_RN;
>> + *infolen = len + sizeof(struct sctp_rcvinfo);
>> + } else {
>> + break;
>> + }
>> + }
>> + }
>> +
>> + return error;
>> +}
>> diff --git a/src/lib/sendmsg.c b/src/lib/sendmsg.c
>> index 9046174..cb75378 100644
>> --- a/src/lib/sendmsg.c
>> +++ b/src/lib/sendmsg.c
>> @@ -19,7 +19,10 @@
>> * Ardelle Fan <ardelle.fan@xxxxxxxxx>
>> */
>>
>> +#include <errno.h>
>> #include <string.h>
>> +#include <stdlib.h>
>> +#include <netinet/in.h>
>> #include <sys/socket.h> /* struct sockaddr_storage, setsockopt() */
>> #include <netinet/sctp.h>
>>
>> @@ -104,3 +107,161 @@ sctp_send(int s, const void *msg, size_t len,
>>
>> return sendmsg(s, &outmsg, flags);
>> }
>> +
>> +static struct cmsghdr *sctp_sendv_store_cmsg(struct cmsghdr *cmsg, int *cmsglen,
>> + int type, int len, void *data)
>> +{
>> + cmsg->cmsg_level = IPPROTO_SCTP;
>> + cmsg->cmsg_type = type;
>> + cmsg->cmsg_len = CMSG_LEN(len);
>> + memcpy(CMSG_DATA(cmsg), data, len);
>> +
>> + *cmsglen -= CMSG_SPACE(len);
>> + if (!*cmsglen)
>> + return NULL;
>> +
>> + return (struct cmsghdr *)((char *)cmsg + CMSG_SPACE(len));
>> +}
>> +
>> +int sctp_sendv(int s, const struct iovec *iov, int iovcnt,
>> + struct sockaddr *addrs, int addrcnt, void *info,
>> + socklen_t infolen, unsigned int infotype, int flags)
>> +{
>> + struct sockaddr *addr;
>> + struct msghdr outmsg;
>> + struct cmsghdr *cmsg;
>> + int type, len, i;
>> + int cmsglen = 0;
>> + char *addrbuf;
>> +
>> + /* set msg_iov, msg_iovlen, msg_flags */
>> + memset(&outmsg, 0x00, sizeof(outmsg));
>> + outmsg.msg_iov = (struct iovec *)iov;
>> + outmsg.msg_iovlen = iovcnt;
>> + outmsg.msg_flags = flags;
>> +
>> + /* set msg_name and msg_namelen */
>> + if (addrs && addrcnt) {
>> + outmsg.msg_name = addrs;
>> + if (addrs->sa_family == AF_INET)
>> + outmsg.msg_namelen = sizeof(struct sockaddr_in);
>> + else if (addrs->sa_family == AF_INET6)
>> + outmsg.msg_namelen = sizeof(struct sockaddr_in6);
>> + else
>> + return -EINVAL;
>> + addrcnt -= 1;
>> + addrbuf = (char *)addrs;
>> + addrs = (struct sockaddr *)(addrbuf + outmsg.msg_namelen);
>> + }
>> +
>> + /* get the cmsg length it will need for addr info */
>> + for (i = 0, addrbuf = (char *)addrs; i < addrcnt; i++) {
>> + addr = (struct sockaddr *)addrbuf;
>> + if (addr->sa_family == AF_INET) {
>> + len = sizeof(struct in_addr);
>> + cmsglen += CMSG_SPACE(len);
>> + addrbuf += sizeof(struct sockaddr_in);
>> + } else if (addr->sa_family == AF_INET6) {
>> + len = sizeof(struct in6_addr);
>> + cmsglen += CMSG_SPACE(len);
>> + addrbuf += sizeof(struct sockaddr_in6);
>> + } else {
>> + return -EINVAL;
>> + }
>> + }
>> + /* get the cmsg length it will need for snd/pr/auth info */
>> + if (infotype == SCTP_SENDV_SPA) {
>> + struct sctp_sendv_spa *spa = info;
>> +
>> + if (spa->sendv_flags & SCTP_SEND_SNDINFO_VALID)
>> + cmsglen += CMSG_SPACE(sizeof(struct sctp_sndinfo));
>> + if (spa->sendv_flags & SCTP_SEND_PRINFO_VALID)
>> + cmsglen += CMSG_SPACE(sizeof(struct sctp_prinfo));
>> + if (spa->sendv_flags & SCTP_SEND_AUTHINFO_VALID)
>> + cmsglen += CMSG_SPACE(sizeof(struct sctp_authinfo));
>> + } else if (infotype == SCTP_SENDV_SNDINFO) {
>> + cmsglen += CMSG_SPACE(sizeof(struct sctp_sndinfo));
>> + } else if (infotype == SCTP_SENDV_PRINFO) {
>> + cmsglen += CMSG_SPACE(sizeof(struct sctp_prinfo));
>> + } else if (infotype == SCTP_SENDV_AUTHINFO) {
>> + cmsglen += CMSG_SPACE(sizeof(struct sctp_authinfo));
>> + }
>> +
> We're talkinag about less than 128 bytes of storage here. Instead of checking
> all the infotypes and allocating the appropriate cmsglen, why not just declare a
> cmsg buffer on the stack that is of the maximum possible size. It would
> eliminate a good deal of code here.
With the appropriate cmsglen, we can void the unncessary alloc by checking
(!cmsglen).
Otherwise we will have to check "!cmsglen && infotype != any of them",
and also to count cmsglen in the 2nd "if-else if" to set the correct value
for outmsg.msg_controllen.
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